The dissimilar 2B06 and 7B04 Al alloy joints were prepared by refill friction stir spot welding(RFSSW),and the microstructural evolution and corrosion behavior of the joints were investigated.Based on microstructural ...The dissimilar 2B06 and 7B04 Al alloy joints were prepared by refill friction stir spot welding(RFSSW),and the microstructural evolution and corrosion behavior of the joints were investigated.Based on microstructural analysis,the welded joints exhibit distinct microstructural zones,including the stir zone(SZ),thermomechanically affected zone(TMAZ),and heat-affected zone(HAZ).The grain size of each zone is in the order of HAZ>TMAZ>SZ.Notably,the TMAZ and HAZ contain significantly larger secondary-phase particles compared to the SZ,with particle size in the HAZ increasing at higher rotational speeds.Electrochemical tests indicate that corrosion susceptibility follows the sequence of HAZ>TMAZ>SZ>BM,with greater sensitivity observed at increased rotational speeds.Post-corrosion mechanical performance degradation primarily arises from crevice corrosion at joint overlaps,but not from the changes in the microstructure.展开更多
This study utilizes wet/dry cyclic corrosion testing combined with corrosion big data technology to investigate the mechanism by which chloride ions(Cl^(-))influence the corrosion behavior of 650 MPa high-strength low...This study utilizes wet/dry cyclic corrosion testing combined with corrosion big data technology to investigate the mechanism by which chloride ions(Cl^(-))influence the corrosion behavior of 650 MPa high-strength low-alloy(HSLA)steel in industrially polluted environments.The corrosion process of 650 MPa HSLA steel occurred in two distinct stages:an initial corrosion stage and a stable corrosion stage.During the initial phase,the weight loss rate increased rapidly owing to the instability of the rust layer.Notably,this study demonstrated that 650 MPa HSLA steel exhibited superior corrosion resistance in Cl-containing environments.The formation of a corrosion-product film eventually reduced the weight-loss rate.However,the intrusion of Cl^(-)at increasing concentrations gradually destabilized theα/γ^(*)phases of the rust layer,leading to a looser structure and lower polarization resistance(R_(p)).The application of corrosion big data technology in this study facilitated the validation and analysis of the experimental results,offering new insights into the corrosion mechanisms of HSLA steel in chloride-rich environments.展开更多
The microstructural characterization,corrosion behavior and tensile properties of the extruded lean Mg−1Bi−0.5Sn−0.5In(wt.%)alloy were investigated through scanning electron microscopy(SEM),electron backscatter diffra...The microstructural characterization,corrosion behavior and tensile properties of the extruded lean Mg−1Bi−0.5Sn−0.5In(wt.%)alloy were investigated through scanning electron microscopy(SEM),electron backscatter diffraction(EBSD),X-ray photoelectron spectroscopy(XPS),electrochemical measurements and tensile tests.The results reveal that a microstructure consisting of dynamically recrystallized and deformed grains is obtained.Notably,the investigated alloy exhibits excellent strength−ductility synergy,with tensile yield strength(TYS),ultimate tensile strength(UTS)and elongation(EL)of 254.8 MPa,315.4 MPa,and 25.3%,respectively.Furthermore,in 3.5 wt.%NaCl solution,with the increase of immersion time,the dominant corrosion mechanism of the studied alloy transforms from pitting corrosion to filiform corrosion.After the immersion for 24 h,a composite oxide film(SnO2−Bi2O3−In2O3)is formed,which delays the corrosion process,and the corrosion rate(PH=1.53 mm/a)is finally stabilized.展开更多
Microstructural characterization,mass loss tests,hydrogen evolution tests,electrochemical measurements,and corrosion morphology observations were conducted to investigate the effect of the secondary phases on the corr...Microstructural characterization,mass loss tests,hydrogen evolution tests,electrochemical measurements,and corrosion morphology observations were conducted to investigate the effect of the secondary phases on the corrosion behavior of the as-cast Mg−7Sn−1Zn−1Y(TZW711)alloy after solution treatment(T4)and aging treatment(T6).The results show that the T4-TZW711 alloy possesses the highest corrosion resistance in the early corrosion stage.This is because the dissolution of Mg2Sn reduces the cathodic current density and increases the charge transfer resistance(Rct).When the corrosion time is prolonged,the undissolved and clustered MgSnY phase will peel off from the T4-TZW711 alloy surface,thereby increasing the corrosion rate of the alloy.After aging treatment,the undissolved MgSnY phase is dispersed,which results in a lower localized corrosion sensitivity of T6-TZW711 alloy than that of the T4-TZW711 alloy,suggesting that the T6 treatment can enhance the corrosion resistance of Mg−7Sn−1Zn−1Y alloys.展开更多
The pre-weld heat treatment was carried out to obtain different initial microstructures of the GH4169 superalloy,and then Linear Friction Welding(LFW)was performed.The effect of the pre-weld heat treatment on the micr...The pre-weld heat treatment was carried out to obtain different initial microstructures of the GH4169 superalloy,and then Linear Friction Welding(LFW)was performed.The effect of the pre-weld heat treatment on the microstructure evolution and mechanical properties of the joint was analyzed,and the joint electrochemical corrosion behavior as well as the hot corrosion behavior was studied.The results show that the joint hardness of Base Metal(BM)increases after pre-weld heat treatment,and the strengthening phasesγ′andγ″further precipitate.However,the precipitation phases dissolve significantly in the Weld Zone(WZ)due to the thermal process of LFW.The corrosion resistance in BM is reduced after the pre-weld heat treatment,while it is similar in WZ with a slight decrease.The surface morphology of the BM and WZ can be generally divided into a loose and porous matrix and a scattered oxide particle layer after hot corrosion.The joint cross section exhibits a Cr-depleted zone with the diffusion of Cr to form an oxide film.The corrosion product mainly consists of Fe_(2)O_(3)/Fe_(3)O_(4) as the outer layer and Cr_(2)O_(3) as the inner layer.展开更多
Magnesium(Mg)alloys have attracted considerable attention as promising implant materials for biodegradable medical devices.In this study,we focused on investigating the effect of macroscopic environmental heterogeneit...Magnesium(Mg)alloys have attracted considerable attention as promising implant materials for biodegradable medical devices.In this study,we focused on investigating the effect of macroscopic environmental heterogeneity due to the degradation of Mg on its corrosion behavior.The immersion experiments using pure Mg plates,which were placed vertically in a culture medium(Dulbecco’s Modified Eagle’s Medium(DEME)+10%fetal bovine serum(FBS))for 1,5,and 10 days,were conducted.Surface analyses for the corrosion product layers and the measurements of the pH values and concentrations of eluted ions in the immersion medium around the upper and lower areas of the Mg plate were performed.The significant effect of the macroscopic environmental heterogeneity derived from Mg degradation on the corrosion behavior was demonstrated by in vitro tests.Additionally,the in vivo tests were carried out by implanting the pure Mg plates in the femur of rabbits.The in vivo results exhibited macroscopically heterogeneous Mg degradation,with areas of more severe corrosion compared to the in vitro test;it is especially noticeable during the early stage of degradation,even though the average corrosion rate was lower.展开更多
Ti-Gd alloys with Gd contents of 2 wt%-8 wt% were prepared,and the influence of Gd content on the microstructure,mechanical properties,corrosion behavior,neutron absorption property and density of the alloy weas inves...Ti-Gd alloys with Gd contents of 2 wt%-8 wt% were prepared,and the influence of Gd content on the microstructure,mechanical properties,corrosion behavior,neutron absorption property and density of the alloy weas investigated.The micro structure changes from full lamellar α phase to fine equiaxed crystals,and the area fraction of Gd-rich phase decreases from 3.2% to 1.8% and then increases to 9.1%.Gd has three existing forms:pure Gd,compound oxide of Gd_(2)TiO_(5)and/or Gd_(2)O_(3)and solidifies in the Ti matrix.Ti-4Gd exhibits the best mechanical properties,its tensile strength and elongation is 102 MPa and 49%,respectively.The neutron transmittancy of Ti-8Gd alloy in water is the lowest,which is 3.75%.The corrosion rate of Ti-Gd alloy is 0.00097-0.00238 mm/a,which meets the corrosion standard of small-scale nuclear reactors and containers for spent fuel.展开更多
NiTi alloy has been widely used as orthopedic implant materials due to its unique shape memory properties and superelasticity.However,implantation failure often occurs because of the poor antibacterial ability,antioxi...NiTi alloy has been widely used as orthopedic implant materials due to its unique shape memory properties and superelasticity.However,implantation failure often occurs because of the poor antibacterial ability,antioxidation property and corrosion resistance of the NiTi alloy.In order to overcome the above problems,we constructed Zn/polydopamine(PDA)/Chitosan-Catechol(CS-C)composite coating on the surface of NiTi alloy in this paper.The surface morphology and wettability of the coating were characterized by scanning electron microscopy(SEM)and optical contact angle measuring instrument,respectively.The results showed that the Zn/CS-C coating was successfully prepared,and exhibited good hydrophilic property,especially the sample Zn/PDA/CS-C-24 h.In addition,the corrosion resistance,antioxidation property and biological properties of the coating were systematically analyzed.The results indicated that the Zn/PDA/CS-C composite coating exhibited good corrosion resistance and antibacterial property,antioxidant property and osteogenic activity,especially sample Zn/PDA/CS-C-24 h.The sample Zn/PDA/CS-C-24 h could effectively protect osteoblasts from reactive oxygen species(ROS)damage and promote cell proliferation and osteoblast differentiation.This study provides a feasible and effective strategy for the surface modification of orthopedic implant.展开更多
The effects of Zr addition on the mechanical properties and in vitro degradation behavior of Mg-1.0Yb-xZr(x=0,0.2,1.0,and 1.53,wt.%)cast alloys were investigated.The results indicated that with increasing Zr addition,...The effects of Zr addition on the mechanical properties and in vitro degradation behavior of Mg-1.0Yb-xZr(x=0,0.2,1.0,and 1.53,wt.%)cast alloys were investigated.The results indicated that with increasing Zr addition,a much refined and homogeneous equiaxed grain structure was achieved from a typical columnar grain structure,in companion with the appearance and coarsening of Zr-rich particles.Subsequent electrochemical and immersion tests demonstrated that the corrosion of the alloy was Zr-addition dependent.A trace or excessive Zr addition caused severe localized corrosion attacks,whereas Zr-free and 1.0 Zr alloyed counterparts were generally corroded uniformly.The good combination of mechanical properties and corrosion resistance of the Mg-1.0Yb-1.0Zr alloy was resulted from the refined and homogeneous equiaxed grain structure and fine dispersed Zr-rich particles,thus improving the comprehensive mechanical properties by grain refinement and reducing corrosion rate by generating a more stable and compact passivation layer during long-term immersion.展开更多
A systematic study was conducted on the microstructure,mechanical properties,and corrosion resistance of Ti-20Zr-xAl-2.5Sn(x=5,7,9,11,and 13 wt.%)quaternary alloy.The microstructure of the rolled alloys was characteri...A systematic study was conducted on the microstructure,mechanical properties,and corrosion resistance of Ti-20Zr-xAl-2.5Sn(x=5,7,9,11,and 13 wt.%)quaternary alloy.The microstructure of the rolled alloys was characterized by optical microscopy,X-ray diffraction,scanning electron microscopy,and transmission electron microscopy.The mechanical properties were analyzed through tensile tests,microhardness tests,and friction wear tests.Corrosion performance was evaluated using electrochemical tests,and X-ray photoelectron spectroscopy was employed to analyze the passivation film on the alloy surface.The results show that increasing Al content improves the mechanical properties of the alloy,but excessive Al leads to the creation of Ti_(3)Al,resulting in a substantial deterioration of the mechanical characteristics of the alloy.The alloy with 7 wt.%Al exhibited the best overall mechanical properties.Electrochemical experiments revealed that higher Al content positively affected the corrosion resistance,with the alloy containing 7 wt.%Al showing the best corrosion resistance,followed by a slight decline.A small amount of Al_(2)O_(3)in the passivation film enhanced the corrosion resistance,but the formation of Al_(2)O_(3)with higher Al content decreased the corrosion performance.展开更多
The influence of alloying dysprosium(Dy)element on the biodegradable behavior and mechanical prop-erty of Mg-6 Zn alloys in a simulated body solution(SBF)solution was studied.The results indicate that Dy significantly...The influence of alloying dysprosium(Dy)element on the biodegradable behavior and mechanical prop-erty of Mg-6 Zn alloys in a simulated body solution(SBF)solution was studied.The results indicate that Dy significantly contributes to grain refinement,and form a distinctive fiber texture in Dy-containing al-loys.The presence of Dy promotes the formation of granular DyZn3 precipitates,which possess a higher electrode potential than the matrix,thus accelerating matrix corrosion.Corrosion results demonstrate that the Dy element is not beneficial to reducing the initial corrosion rate of Mg-6 Zn but is conducive to improving the protective effect of product film as the immersion time increases.Dy-containing alloys exhibit higher strength than Mg-6 Zn while maintaining good plasticity related to grain boundary and precipitation strength effects.Consequently,the incorporation of 2 wt.%Dy into Mg-6 Zn alloys results in a synergistic enhancement of strength,as well as moderate corrosion resistance and fracture elongation.展开更多
This work investigated tribological behavior and corrosion resistance of laser cladding(LC)Ti_(50)Nb_(15)V_(15)Zr_(5)Cr_(5)Al_(10)high-entropy alloy(HEA)coatings on Ti6Al4V substrates.Microstructural characterization ...This work investigated tribological behavior and corrosion resistance of laser cladding(LC)Ti_(50)Nb_(15)V_(15)Zr_(5)Cr_(5)Al_(10)high-entropy alloy(HEA)coatings on Ti6Al4V substrates.Microstructural characterization illustrated that there was only body centered cubic phase in the HEA coating.Besides,the coatings of different laser power all exhibited obviously higher hardness than the substrate.It is illustrated that the microstructure of the HEA coatings is composed of body centered cubic phase,and the temperature gradient contributes to the distribution difference between the equiaxed and columnar grains.Meanwhile,the relationships between the tribological behavior,corrosion resistance and alloying elements have been illustrated.The HEA coating with 2200 W holds the best wear and corrosion resistance.During the friction process,there are many oxides formed at high temperatures,and adhesive wear contributes most to the wear mechanism of the coatings.The wear volumes of the HEA coatings are only 24.7%to 45.5%of that of the Ti6Al4V substrate.Due to the alloying elements like Cr and Al,there is dense passive film formed during the corrosion process,thereby leading to better corrosion resistance of the coatings.The corrosion rates of the HEA coatings with 2200 W and Ti6Al4V substrate are 5.34×10^(-3)mm/a and 2.69×10^(-2)mm/a,respectively.展开更多
Hot corrosion in molten salt is a complex process,involving both chemical corrosion and electrochemical corrosion.Interfacial reactions and oxide dissolution can also impact the corrosion results.Compared with single ...Hot corrosion in molten salt is a complex process,involving both chemical corrosion and electrochemical corrosion.Interfacial reactions and oxide dissolution can also impact the corrosion results.Compared with single component/type salt,multicomponent/type hot corrosion leads to more severe degradation,while the multi-component alloys offer potential chances for developing anti-corrosion metallic materials.In this study,we aim to elucidate the hot corrosion behavior and gain a better understanding of the corrosion mechanism of the multi-component alloys under multi-component/type NaCl-KCl-Na_(2)SO_(4)salt.The corrosion behavior of dual-phaseNi_(36)Fe_(34)Al_(17)Cr_(10)Mo_(1)Ti_(2)(HEA-1)and Ni_(34)Co_(25)Fe_(12)Al_(15)Cr_(12)W_(2)(HEA-2)alloys was studied within NaCl-KCl-Na_(2)SO_(4)molten salt with mass ratios of 5:5:1 and 5:5:2.After exposure to the salt at 650°C for 168 h,it was found that the Ni_(34)Co_(25)Fe_(12)Al_(15)Cr_(12)W_(2)exhibited better corrosion resistance thanNi_(36)Fe_(34)Al_(17)Cr_(10)Mo_(1)Ti_(2).The improved performance of Ni_(30)Co_(25)Fe_(12)Al_(15)Cr_(12)W_(2)alloy was attributed to the Co element,which facilitated the formation of dense oxides scale and enhanced scale adhesion.Alkali chlorides with stronger penetration ability dominated the corrosion process and alkali sulfate further aggravated the corrosion.The primary corrosion mechanisms involved in this process were identified as“electrochemical mechanism”attacking the body-centered cubic structure in the alloys and“active oxidation”causing dissolution of the alloy elements.展开更多
The effect of Cl^(–)and SO_(4)^(2–)on corrosion behavior of pure copper in simulated groundwater was investigated by electrochemical testing techniques,scanning electron microscope/energy dispersive spectroscopy,X-r...The effect of Cl^(–)and SO_(4)^(2–)on corrosion behavior of pure copper in simulated groundwater was investigated by electrochemical testing techniques,scanning electron microscope/energy dispersive spectroscopy,X-ray photoelectron spectroscopy,and X-ray diffraction in 0.1 mol/L NaHCO_(3)solutions.The results indicate that increasing Cl^(-)and SO_(4)^(2–)reduces the corrosion resistance of Cu.Cl^(-)and SO_(4)^(2–)can promote anodic dissolution of Cu and deteriorate the passivation property.The breakdown potential(Eb)of Cu decreases with the increase in Cl^(-)and SO_(4)^(2–).With the increase in immersion time,the polarization resistance in different solutions tends to be stable.After 55 days,polarization resistance(Rp)was almost equal in 0 and 0.01 mol/L Cl^(-)and SO_(4)^(2–)solutions.In 0.05 mol/L Cl^(-)and SO_(4)^(2−)solution,Rp was lower.HCO3–has a certain corrosion effect on Cu and the pits size increased with the increase in Cl^(-)and SO_(4)^(2–).The corrosion products(Cu_(2)(OH)_(2)CO_(3))and CuO were detected in solutions without or at low Cl^(-)and SO_(4)^(2–)contents.The corrosion product after immersion in the solution containing 0.05 mol/L Cl^(-)and SO_(4)^(2–)was Cu_(2)O.展开更多
The corrosion behavior of Q420 steel under constant temperature and freezing-thawing conditions is investigated.The steel exhibits the highest corrosion rate at 25℃ and the lowest corrosion rate at−30℃,while the ste...The corrosion behavior of Q420 steel under constant temperature and freezing-thawing conditions is investigated.The steel exhibits the highest corrosion rate at 25℃ and the lowest corrosion rate at−30℃,while the steel that undergoes freezing-thawing cycling shows lower corrosion rate than that at 0℃.The localized corrosion is significantly affected by the temperature variations,with the samples corroded under freezing-thawing conditions showing the highest pit number density and the highest possibility of the pit initiation.The samples immersed at 0 and 25℃ show comparable pit size with higher pit depth,diameter,and volume,attributed to the higher rate of pit propagation along the vertical and horizontal directions.Galvanic corrosion results demonstrate that there are areas of activated metal under the ice,which form microcells with surrounding unaffected areas,attributed to the local ion concentration and the water crystallization.展开更多
Magnesium alloys hold promise as biodegradable orthopedic implants but suffer from rapid corrosion and poor corrosion fatigue performance.This study evaluates the efficacy of a micro-arc oxidation(MAO)layer combined w...Magnesium alloys hold promise as biodegradable orthopedic implants but suffer from rapid corrosion and poor corrosion fatigue performance.This study evaluates the efficacy of a micro-arc oxidation(MAO)layer combined with 3-glycidyloxypropyltrimethoxysilane(GPTMS)sealing in enhancing the corrosion fatigue behavior of ZE21B magnesium alloy in Hanks’Balanced Salt Solution(HBSS).Electrochemical testing revealed a two-order-of-magnitude reduction in corrosion current density compared to bare alloy,while immersion tests demonstrated sustained protection against degradation.Corrosion fatigue experiments under cyclic loading showed stress-dependent performance:the composite coating improved fatigue life at low stress amplitudes(60 MPa)by mitigating corrosion pit formation,but interfacial weakness between GPTMS and MAO layers reduced performance at high stresses(90-80 MPa).Fractographic analysis identified asynchronous deformation and stress gradient-dependent coating spallation as key failure modes.These results provide mechanistic insights into coating degradation pathways and offer design strategies for developing robust surface modification systems to advance magnesium-based orthopedic applications.展开更多
The corrosion behavior and life of Sn−3.0Ag−0.5Cu solder joints were investigated through fire smoke exposure experiments within the temperature range of 45−80℃.The nonlinear Wiener process and Arrhenius equation wer...The corrosion behavior and life of Sn−3.0Ag−0.5Cu solder joints were investigated through fire smoke exposure experiments within the temperature range of 45−80℃.The nonlinear Wiener process and Arrhenius equation were used to establish the probability distribution function and prediction model of the solder joint’s average life and individual remaining useful life.The results indicate that solder joint resistance shows a nonlinear growth trend with time increasing.After 24 h,the solder joint transforms from spherical to rose-like shapes.Higher temperatures accelerate solder joint failure,and the relationship between failure time and temperature conforms to the Arrhenius equation.The predicted life of the model is in good agreement with experimental results,demonstrating the effectiveness and accuracy of the model.展开更多
Developing cost-efective and high-performance magnesium alloys is a key focus in lightweight materials applications.In this work,a Mg extrusion alloy with a remarkable cost-performance advantage was prepared by microa...Developing cost-efective and high-performance magnesium alloys is a key focus in lightweight materials applications.In this work,a Mg extrusion alloy with a remarkable cost-performance advantage was prepared by microalloying with costefective zirconium and adjusting the deformation temperature.Investigations revealed that both the degree of dynamic recrystallization(DRX)and the average grain size increased with increasing extrusion temperature,developing a more homogeneous microstructure.Although all samples exhibited a typical basal texture,a progressive spreading of crystallographic orientations along the<10–10>–<11–20>arc became increasingly pronounced with elevated extrusion temperatures.At a low extrusion temperature of 200℃,the heterogeneous microstructure and strong basal texture favored texture and grain boundary strengthening,resulting in the largest yield strength of~244 MPa.However,the potential diference between coarse and fne grains aggravated localized corrosion with a higher corrosion rate of~14.56 mm/y.Conversely,at a high extrusion temperature of 320℃,the coarse grains and weak basal texture enhanced dislocation storage and the activation of multiple slip systems during axial tension,providing better strain hardening ability and the largest ductility of~13.6%.Nevertheless,grain coarsening and texture weakening were detrimental to mechanical strength(~162 MPa).Interestingly,extrusion at 250℃ developed a good combination of grain size,microstructure homogeneity,and texture intensity,achieving synergistic enhancement in grain boundary strengthening,dislocation storage,and uniform corrosion.Thus,a balanced yield strength of~185 MPa,ductility of~12.9%,and corrosion rate of~4.31 mm/y were obtained in this sample.展开更多
This study develops novel Mg-Sn-In-Ga alloys as potential implant materials for orthopedic applications.The corrosion behavior of the Mg-Sn-In-Ga alloys was studied through mass loss measurements,hydrogen evolution me...This study develops novel Mg-Sn-In-Ga alloys as potential implant materials for orthopedic applications.The corrosion behavior of the Mg-Sn-In-Ga alloys was studied through mass loss measurements,hydrogen evolution measurements,electrochemical analysis,and corrosion morphology observations.The results show that the corrosion rate of the Mg-1Sn-1In-1Ga alloy was only 0.10±0.003 mm/y after immersion in Hank’s solution for 15 days.This outstanding corrosion resistance was associated with the protective efect of the corrosion products.The increase in the Sn and Ga element content led to the precipitation of a large amount of Mg_(2)Sn and Mg_(5)Ga_(2),which had a dominant efect on the corrosion rate in the Mg-5Sn-1In-2Ga alloy.These precipitates increased the current density and detached from the alloy surface during the corrosion process.This can lead to a weakened protective efect of the corrosion layer,and thus generate localized corrosion and an increase in the corrosion rate.The strength of the Mg-5Sn-1In-2Ga alloy was enhanced due to fne-grain strengthening and precipitation strengthening.The ultimate tensile strength and yield strength of the Mg-5Sn-1In-2Ga alloy were~309 MPa and~253 MPa,respectively.展开更多
The new energy vehicle body composed of multi-metals requires a synchronous chemical conversion coating to exhibit excellent corrosion resistance.Herein,we prepared a titanium/zirconium/water-based oligomeric epoxy si...The new energy vehicle body composed of multi-metals requires a synchronous chemical conversion coating to exhibit excellent corrosion resistance.Herein,we prepared a titanium/zirconium/water-based oligomeric epoxy silane composite chemical conversion coating on multi-metals,and conducted an investigation into its electrochemical behavior and micro-zone structural characteristics upon immersion in a 3.5%NaCl solution.The electrochemical results combined with characterization results revealed that the corrosion evolution characteristics of the composite coatings could be categorized into three stages of mild corrosion,synergistic protection,and substrate damage.Besides,Si-OH groups interact with Me-OH at the defect on the multi-metal surface to form an organic monolayer coating.This organic monolayer coating,in conjunction with the synergistic inorganic conversion layer comprising Al_(2)O_(3),TiO_(2),2H_(2)O,ZrO_(2),2H_(2)O,effectively cooperates with the corrosion products to hinder the erosion by the corrosive medium and suppresses the progression of the anodic reaction.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 52075449, 51975480)。
文摘The dissimilar 2B06 and 7B04 Al alloy joints were prepared by refill friction stir spot welding(RFSSW),and the microstructural evolution and corrosion behavior of the joints were investigated.Based on microstructural analysis,the welded joints exhibit distinct microstructural zones,including the stir zone(SZ),thermomechanically affected zone(TMAZ),and heat-affected zone(HAZ).The grain size of each zone is in the order of HAZ>TMAZ>SZ.Notably,the TMAZ and HAZ contain significantly larger secondary-phase particles compared to the SZ,with particle size in the HAZ increasing at higher rotational speeds.Electrochemical tests indicate that corrosion susceptibility follows the sequence of HAZ>TMAZ>SZ>BM,with greater sensitivity observed at increased rotational speeds.Post-corrosion mechanical performance degradation primarily arises from crevice corrosion at joint overlaps,but not from the changes in the microstructure.
基金financially supported by the National Natural Science Foundation of China(Nos.52104319 and 52374323)。
文摘This study utilizes wet/dry cyclic corrosion testing combined with corrosion big data technology to investigate the mechanism by which chloride ions(Cl^(-))influence the corrosion behavior of 650 MPa high-strength low-alloy(HSLA)steel in industrially polluted environments.The corrosion process of 650 MPa HSLA steel occurred in two distinct stages:an initial corrosion stage and a stable corrosion stage.During the initial phase,the weight loss rate increased rapidly owing to the instability of the rust layer.Notably,this study demonstrated that 650 MPa HSLA steel exhibited superior corrosion resistance in Cl-containing environments.The formation of a corrosion-product film eventually reduced the weight-loss rate.However,the intrusion of Cl^(-)at increasing concentrations gradually destabilized theα/γ^(*)phases of the rust layer,leading to a looser structure and lower polarization resistance(R_(p)).The application of corrosion big data technology in this study facilitated the validation and analysis of the experimental results,offering new insights into the corrosion mechanisms of HSLA steel in chloride-rich environments.
基金supported by the National Natural Science Foundation of China(No.51901153)the Natural Science Foundation of Shanxi,China(No.202103021224049)+1 种基金the Shanxi Zhejiang University New Materials and Chemical Research Institute Scientific Research Project,China(No.2022SX-TD025)the Open Project of Salt Lake Chemical Engineering Research Complex,Qinghai University,China(No.2023-DXSSKF-Z02).
文摘The microstructural characterization,corrosion behavior and tensile properties of the extruded lean Mg−1Bi−0.5Sn−0.5In(wt.%)alloy were investigated through scanning electron microscopy(SEM),electron backscatter diffraction(EBSD),X-ray photoelectron spectroscopy(XPS),electrochemical measurements and tensile tests.The results reveal that a microstructure consisting of dynamically recrystallized and deformed grains is obtained.Notably,the investigated alloy exhibits excellent strength−ductility synergy,with tensile yield strength(TYS),ultimate tensile strength(UTS)and elongation(EL)of 254.8 MPa,315.4 MPa,and 25.3%,respectively.Furthermore,in 3.5 wt.%NaCl solution,with the increase of immersion time,the dominant corrosion mechanism of the studied alloy transforms from pitting corrosion to filiform corrosion.After the immersion for 24 h,a composite oxide film(SnO2−Bi2O3−In2O3)is formed,which delays the corrosion process,and the corrosion rate(PH=1.53 mm/a)is finally stabilized.
基金National Natural Science Foundation of China(Nos.52301041,52022017,52065009,52371005)Special Fund for Special Posts of Guizhou University,China(No.[2023]26)+1 种基金Science and Technology Planning Project of Guizhou Province,China(No.ZK2021269)Fundamental Research Funds for the Central Universities,China(No.DUT23YG104)。
文摘Microstructural characterization,mass loss tests,hydrogen evolution tests,electrochemical measurements,and corrosion morphology observations were conducted to investigate the effect of the secondary phases on the corrosion behavior of the as-cast Mg−7Sn−1Zn−1Y(TZW711)alloy after solution treatment(T4)and aging treatment(T6).The results show that the T4-TZW711 alloy possesses the highest corrosion resistance in the early corrosion stage.This is because the dissolution of Mg2Sn reduces the cathodic current density and increases the charge transfer resistance(Rct).When the corrosion time is prolonged,the undissolved and clustered MgSnY phase will peel off from the T4-TZW711 alloy surface,thereby increasing the corrosion rate of the alloy.After aging treatment,the undissolved MgSnY phase is dispersed,which results in a lower localized corrosion sensitivity of T6-TZW711 alloy than that of the T4-TZW711 alloy,suggesting that the T6 treatment can enhance the corrosion resistance of Mg−7Sn−1Zn−1Y alloys.
基金supported by the National Natural Science Foundation of China(Nos.52074228,52305420 and 51875470)the Practice and Innovation Funds for Graduate Students of Northwestern Polytechnical University,China(No.PF2024053)the Xi’an Beilin District Science and Technology Planning Project,China(No.GX2349).
文摘The pre-weld heat treatment was carried out to obtain different initial microstructures of the GH4169 superalloy,and then Linear Friction Welding(LFW)was performed.The effect of the pre-weld heat treatment on the microstructure evolution and mechanical properties of the joint was analyzed,and the joint electrochemical corrosion behavior as well as the hot corrosion behavior was studied.The results show that the joint hardness of Base Metal(BM)increases after pre-weld heat treatment,and the strengthening phasesγ′andγ″further precipitate.However,the precipitation phases dissolve significantly in the Weld Zone(WZ)due to the thermal process of LFW.The corrosion resistance in BM is reduced after the pre-weld heat treatment,while it is similar in WZ with a slight decrease.The surface morphology of the BM and WZ can be generally divided into a loose and porous matrix and a scattered oxide particle layer after hot corrosion.The joint cross section exhibits a Cr-depleted zone with the diffusion of Cr to form an oxide film.The corrosion product mainly consists of Fe_(2)O_(3)/Fe_(3)O_(4) as the outer layer and Cr_(2)O_(3) as the inner layer.
基金supported by JSPS KAKENHI Grant Number 22K12903.
文摘Magnesium(Mg)alloys have attracted considerable attention as promising implant materials for biodegradable medical devices.In this study,we focused on investigating the effect of macroscopic environmental heterogeneity due to the degradation of Mg on its corrosion behavior.The immersion experiments using pure Mg plates,which were placed vertically in a culture medium(Dulbecco’s Modified Eagle’s Medium(DEME)+10%fetal bovine serum(FBS))for 1,5,and 10 days,were conducted.Surface analyses for the corrosion product layers and the measurements of the pH values and concentrations of eluted ions in the immersion medium around the upper and lower areas of the Mg plate were performed.The significant effect of the macroscopic environmental heterogeneity derived from Mg degradation on the corrosion behavior was demonstrated by in vitro tests.Additionally,the in vivo tests were carried out by implanting the pure Mg plates in the femur of rabbits.The in vivo results exhibited macroscopically heterogeneous Mg degradation,with areas of more severe corrosion compared to the in vitro test;it is especially noticeable during the early stage of degradation,even though the average corrosion rate was lower.
基金Project supported by the National Key R&D Program of China (2023YFB3506703)。
文摘Ti-Gd alloys with Gd contents of 2 wt%-8 wt% were prepared,and the influence of Gd content on the microstructure,mechanical properties,corrosion behavior,neutron absorption property and density of the alloy weas investigated.The micro structure changes from full lamellar α phase to fine equiaxed crystals,and the area fraction of Gd-rich phase decreases from 3.2% to 1.8% and then increases to 9.1%.Gd has three existing forms:pure Gd,compound oxide of Gd_(2)TiO_(5)and/or Gd_(2)O_(3)and solidifies in the Ti matrix.Ti-4Gd exhibits the best mechanical properties,its tensile strength and elongation is 102 MPa and 49%,respectively.The neutron transmittancy of Ti-8Gd alloy in water is the lowest,which is 3.75%.The corrosion rate of Ti-Gd alloy is 0.00097-0.00238 mm/a,which meets the corrosion standard of small-scale nuclear reactors and containers for spent fuel.
基金jointly supported by the Natural Science Foundation of Shanxi Province(Nos.202203021222127,202403021212109).
文摘NiTi alloy has been widely used as orthopedic implant materials due to its unique shape memory properties and superelasticity.However,implantation failure often occurs because of the poor antibacterial ability,antioxidation property and corrosion resistance of the NiTi alloy.In order to overcome the above problems,we constructed Zn/polydopamine(PDA)/Chitosan-Catechol(CS-C)composite coating on the surface of NiTi alloy in this paper.The surface morphology and wettability of the coating were characterized by scanning electron microscopy(SEM)and optical contact angle measuring instrument,respectively.The results showed that the Zn/CS-C coating was successfully prepared,and exhibited good hydrophilic property,especially the sample Zn/PDA/CS-C-24 h.In addition,the corrosion resistance,antioxidation property and biological properties of the coating were systematically analyzed.The results indicated that the Zn/PDA/CS-C composite coating exhibited good corrosion resistance and antibacterial property,antioxidant property and osteogenic activity,especially sample Zn/PDA/CS-C-24 h.The sample Zn/PDA/CS-C-24 h could effectively protect osteoblasts from reactive oxygen species(ROS)damage and promote cell proliferation and osteoblast differentiation.This study provides a feasible and effective strategy for the surface modification of orthopedic implant.
基金the financial supports from the China Scholarship Council(No.201808505057)。
文摘The effects of Zr addition on the mechanical properties and in vitro degradation behavior of Mg-1.0Yb-xZr(x=0,0.2,1.0,and 1.53,wt.%)cast alloys were investigated.The results indicated that with increasing Zr addition,a much refined and homogeneous equiaxed grain structure was achieved from a typical columnar grain structure,in companion with the appearance and coarsening of Zr-rich particles.Subsequent electrochemical and immersion tests demonstrated that the corrosion of the alloy was Zr-addition dependent.A trace or excessive Zr addition caused severe localized corrosion attacks,whereas Zr-free and 1.0 Zr alloyed counterparts were generally corroded uniformly.The good combination of mechanical properties and corrosion resistance of the Mg-1.0Yb-1.0Zr alloy was resulted from the refined and homogeneous equiaxed grain structure and fine dispersed Zr-rich particles,thus improving the comprehensive mechanical properties by grain refinement and reducing corrosion rate by generating a more stable and compact passivation layer during long-term immersion.
基金supported by the National Natural Science Foundation of China(Grant Nos.52474406,52405226,and 52071126)the Natural Science Foundation of Hebei Province of China(Grant No.E2024202254)+2 种基金the Natural Science Foundation of Tianjin City China(Grant No.22JCQNJC01240)the Central Guidance on Local Science and Technology Development Fund of Hebei Province(Grant No.226Z1009G)the Special funds for science and technology innovation in Hebei(Grant No.2022X19).
文摘A systematic study was conducted on the microstructure,mechanical properties,and corrosion resistance of Ti-20Zr-xAl-2.5Sn(x=5,7,9,11,and 13 wt.%)quaternary alloy.The microstructure of the rolled alloys was characterized by optical microscopy,X-ray diffraction,scanning electron microscopy,and transmission electron microscopy.The mechanical properties were analyzed through tensile tests,microhardness tests,and friction wear tests.Corrosion performance was evaluated using electrochemical tests,and X-ray photoelectron spectroscopy was employed to analyze the passivation film on the alloy surface.The results show that increasing Al content improves the mechanical properties of the alloy,but excessive Al leads to the creation of Ti_(3)Al,resulting in a substantial deterioration of the mechanical characteristics of the alloy.The alloy with 7 wt.%Al exhibited the best overall mechanical properties.Electrochemical experiments revealed that higher Al content positively affected the corrosion resistance,with the alloy containing 7 wt.%Al showing the best corrosion resistance,followed by a slight decline.A small amount of Al_(2)O_(3)in the passivation film enhanced the corrosion resistance,but the formation of Al_(2)O_(3)with higher Al content decreased the corrosion performance.
基金supported by the National Natural Science Foundation of China(No.52301133)the China Postdoctoral Science Foundation(No.2023M730276)the Young Elite Scientists Sponsorship Program by China Association for Science and Technology(No.YESS20210415).
文摘The influence of alloying dysprosium(Dy)element on the biodegradable behavior and mechanical prop-erty of Mg-6 Zn alloys in a simulated body solution(SBF)solution was studied.The results indicate that Dy significantly contributes to grain refinement,and form a distinctive fiber texture in Dy-containing al-loys.The presence of Dy promotes the formation of granular DyZn3 precipitates,which possess a higher electrode potential than the matrix,thus accelerating matrix corrosion.Corrosion results demonstrate that the Dy element is not beneficial to reducing the initial corrosion rate of Mg-6 Zn but is conducive to improving the protective effect of product film as the immersion time increases.Dy-containing alloys exhibit higher strength than Mg-6 Zn while maintaining good plasticity related to grain boundary and precipitation strength effects.Consequently,the incorporation of 2 wt.%Dy into Mg-6 Zn alloys results in a synergistic enhancement of strength,as well as moderate corrosion resistance and fracture elongation.
基金Projects(2022YFC2406000,52201067)supported by the National Natural Science Foundation of ChinaProject(2019BT02C629)supported by the Guangdong Special Support Program,China+8 种基金Project(2022GDASZH-2022010107)supported by the Guangdong Academy of Science Projects,ChinaProject(2022GDASZH-2022010203-003)supported by GDAS Projects of International Cooperation Platform of Science and Technology,ChinaProject(2022B1515250004)supported by the Guangdong Basic and Applied Basic Research Foundation,ChinaProjects(2023B1212120008,2023B1212060045)supported by the Guangdong Province Science and Technology Plan Projects,ChinaProject(2024KTSCX191)supported by the Guangdong Province General University Characteristic Innovation Project,ChinaProject(SKXRC202403)supported by the Guangdong Association for Science and Technology,ChinaProjects(QT-2023-038,QT2024-016)supported by the Young Talent Support Project of Guangzhou Association for Science and Technology,ChinaProject(023AFB057)supported by the Natural Science Foundation of Hubei Province,ChinaProject(2023780200040009603)supported by the Jiangmen Science and Technology Plan Projects,China。
文摘This work investigated tribological behavior and corrosion resistance of laser cladding(LC)Ti_(50)Nb_(15)V_(15)Zr_(5)Cr_(5)Al_(10)high-entropy alloy(HEA)coatings on Ti6Al4V substrates.Microstructural characterization illustrated that there was only body centered cubic phase in the HEA coating.Besides,the coatings of different laser power all exhibited obviously higher hardness than the substrate.It is illustrated that the microstructure of the HEA coatings is composed of body centered cubic phase,and the temperature gradient contributes to the distribution difference between the equiaxed and columnar grains.Meanwhile,the relationships between the tribological behavior,corrosion resistance and alloying elements have been illustrated.The HEA coating with 2200 W holds the best wear and corrosion resistance.During the friction process,there are many oxides formed at high temperatures,and adhesive wear contributes most to the wear mechanism of the coatings.The wear volumes of the HEA coatings are only 24.7%to 45.5%of that of the Ti6Al4V substrate.Due to the alloying elements like Cr and Al,there is dense passive film formed during the corrosion process,thereby leading to better corrosion resistance of the coatings.The corrosion rates of the HEA coatings with 2200 W and Ti6Al4V substrate are 5.34×10^(-3)mm/a and 2.69×10^(-2)mm/a,respectively.
基金supported by the National Natural Science Foundation of China(No.51874245)the Natural Science Basic Research Program of Shaanxi(Program No.2022JC-28).
文摘Hot corrosion in molten salt is a complex process,involving both chemical corrosion and electrochemical corrosion.Interfacial reactions and oxide dissolution can also impact the corrosion results.Compared with single component/type salt,multicomponent/type hot corrosion leads to more severe degradation,while the multi-component alloys offer potential chances for developing anti-corrosion metallic materials.In this study,we aim to elucidate the hot corrosion behavior and gain a better understanding of the corrosion mechanism of the multi-component alloys under multi-component/type NaCl-KCl-Na_(2)SO_(4)salt.The corrosion behavior of dual-phaseNi_(36)Fe_(34)Al_(17)Cr_(10)Mo_(1)Ti_(2)(HEA-1)and Ni_(34)Co_(25)Fe_(12)Al_(15)Cr_(12)W_(2)(HEA-2)alloys was studied within NaCl-KCl-Na_(2)SO_(4)molten salt with mass ratios of 5:5:1 and 5:5:2.After exposure to the salt at 650°C for 168 h,it was found that the Ni_(34)Co_(25)Fe_(12)Al_(15)Cr_(12)W_(2)exhibited better corrosion resistance thanNi_(36)Fe_(34)Al_(17)Cr_(10)Mo_(1)Ti_(2).The improved performance of Ni_(30)Co_(25)Fe_(12)Al_(15)Cr_(12)W_(2)alloy was attributed to the Co element,which facilitated the formation of dense oxides scale and enhanced scale adhesion.Alkali chlorides with stronger penetration ability dominated the corrosion process and alkali sulfate further aggravated the corrosion.The primary corrosion mechanisms involved in this process were identified as“electrochemical mechanism”attacking the body-centered cubic structure in the alloys and“active oxidation”causing dissolution of the alloy elements.
基金supported by the National Natural Science Foundation of China(No.U22B2065).
文摘The effect of Cl^(–)and SO_(4)^(2–)on corrosion behavior of pure copper in simulated groundwater was investigated by electrochemical testing techniques,scanning electron microscope/energy dispersive spectroscopy,X-ray photoelectron spectroscopy,and X-ray diffraction in 0.1 mol/L NaHCO_(3)solutions.The results indicate that increasing Cl^(-)and SO_(4)^(2–)reduces the corrosion resistance of Cu.Cl^(-)and SO_(4)^(2–)can promote anodic dissolution of Cu and deteriorate the passivation property.The breakdown potential(Eb)of Cu decreases with the increase in Cl^(-)and SO_(4)^(2–).With the increase in immersion time,the polarization resistance in different solutions tends to be stable.After 55 days,polarization resistance(Rp)was almost equal in 0 and 0.01 mol/L Cl^(-)and SO_(4)^(2–)solutions.In 0.05 mol/L Cl^(-)and SO_(4)^(2−)solution,Rp was lower.HCO3–has a certain corrosion effect on Cu and the pits size increased with the increase in Cl^(-)and SO_(4)^(2–).The corrosion products(Cu_(2)(OH)_(2)CO_(3))and CuO were detected in solutions without or at low Cl^(-)and SO_(4)^(2–)contents.The corrosion product after immersion in the solution containing 0.05 mol/L Cl^(-)and SO_(4)^(2–)was Cu_(2)O.
基金National Key Research and Development Program of China(No.2023YFB3710300)the Key R&D Program of Shandong Province(No.2023CXGC010406)+2 种基金the National Natural Science Foundation of China(No.52371080)the Natural Science Foundation of Shandong Province(ZR2024JQ028)the Project of Taishan Scholars(tsqn202312107).
文摘The corrosion behavior of Q420 steel under constant temperature and freezing-thawing conditions is investigated.The steel exhibits the highest corrosion rate at 25℃ and the lowest corrosion rate at−30℃,while the steel that undergoes freezing-thawing cycling shows lower corrosion rate than that at 0℃.The localized corrosion is significantly affected by the temperature variations,with the samples corroded under freezing-thawing conditions showing the highest pit number density and the highest possibility of the pit initiation.The samples immersed at 0 and 25℃ show comparable pit size with higher pit depth,diameter,and volume,attributed to the higher rate of pit propagation along the vertical and horizontal directions.Galvanic corrosion results demonstrate that there are areas of activated metal under the ice,which form microcells with surrounding unaffected areas,attributed to the local ion concentration and the water crystallization.
基金the National Natural Science Foundation of China(52301107)the Joint Fund Project of Henan Provincial Science and Technology Research and Development Plan(242301420036).
文摘Magnesium alloys hold promise as biodegradable orthopedic implants but suffer from rapid corrosion and poor corrosion fatigue performance.This study evaluates the efficacy of a micro-arc oxidation(MAO)layer combined with 3-glycidyloxypropyltrimethoxysilane(GPTMS)sealing in enhancing the corrosion fatigue behavior of ZE21B magnesium alloy in Hanks’Balanced Salt Solution(HBSS).Electrochemical testing revealed a two-order-of-magnitude reduction in corrosion current density compared to bare alloy,while immersion tests demonstrated sustained protection against degradation.Corrosion fatigue experiments under cyclic loading showed stress-dependent performance:the composite coating improved fatigue life at low stress amplitudes(60 MPa)by mitigating corrosion pit formation,but interfacial weakness between GPTMS and MAO layers reduced performance at high stresses(90-80 MPa).Fractographic analysis identified asynchronous deformation and stress gradient-dependent coating spallation as key failure modes.These results provide mechanistic insights into coating degradation pathways and offer design strategies for developing robust surface modification systems to advance magnesium-based orthopedic applications.
基金National Natural Science Foundation of China (No. 52206180)Fundamental Research Funds for the Central Universities,China (No. WK2320000050)。
文摘The corrosion behavior and life of Sn−3.0Ag−0.5Cu solder joints were investigated through fire smoke exposure experiments within the temperature range of 45−80℃.The nonlinear Wiener process and Arrhenius equation were used to establish the probability distribution function and prediction model of the solder joint’s average life and individual remaining useful life.The results indicate that solder joint resistance shows a nonlinear growth trend with time increasing.After 24 h,the solder joint transforms from spherical to rose-like shapes.Higher temperatures accelerate solder joint failure,and the relationship between failure time and temperature conforms to the Arrhenius equation.The predicted life of the model is in good agreement with experimental results,demonstrating the effectiveness and accuracy of the model.
基金supported by the Natural Science Foundation Project of CQ CSTC(Grant Nos.CSTB2024NSCQ-MSX0473 and CSTC2020JCYJ-MSXMX0170)the National Natural Science Foundation of China(Grant No.51975484)the Research Initiation Project under the Talent Introduction Program at Southwest University(Grant No.SWU-KR24001).
文摘Developing cost-efective and high-performance magnesium alloys is a key focus in lightweight materials applications.In this work,a Mg extrusion alloy with a remarkable cost-performance advantage was prepared by microalloying with costefective zirconium and adjusting the deformation temperature.Investigations revealed that both the degree of dynamic recrystallization(DRX)and the average grain size increased with increasing extrusion temperature,developing a more homogeneous microstructure.Although all samples exhibited a typical basal texture,a progressive spreading of crystallographic orientations along the<10–10>–<11–20>arc became increasingly pronounced with elevated extrusion temperatures.At a low extrusion temperature of 200℃,the heterogeneous microstructure and strong basal texture favored texture and grain boundary strengthening,resulting in the largest yield strength of~244 MPa.However,the potential diference between coarse and fne grains aggravated localized corrosion with a higher corrosion rate of~14.56 mm/y.Conversely,at a high extrusion temperature of 320℃,the coarse grains and weak basal texture enhanced dislocation storage and the activation of multiple slip systems during axial tension,providing better strain hardening ability and the largest ductility of~13.6%.Nevertheless,grain coarsening and texture weakening were detrimental to mechanical strength(~162 MPa).Interestingly,extrusion at 250℃ developed a good combination of grain size,microstructure homogeneity,and texture intensity,achieving synergistic enhancement in grain boundary strengthening,dislocation storage,and uniform corrosion.Thus,a balanced yield strength of~185 MPa,ductility of~12.9%,and corrosion rate of~4.31 mm/y were obtained in this sample.
基金supported by the National Natural Science Foundation of China(No.52301041)the Guizhou Provincial Basic Research Program(No.QianKeHeJiChu-ZK[2024]YiBan036)+1 种基金the Special Fund for Special Posts of Guizhou University(No.[2023]26)the Fundamental Research Funds for the Central Universities.E.G.thanks support from Xiaomi Foundation.
文摘This study develops novel Mg-Sn-In-Ga alloys as potential implant materials for orthopedic applications.The corrosion behavior of the Mg-Sn-In-Ga alloys was studied through mass loss measurements,hydrogen evolution measurements,electrochemical analysis,and corrosion morphology observations.The results show that the corrosion rate of the Mg-1Sn-1In-1Ga alloy was only 0.10±0.003 mm/y after immersion in Hank’s solution for 15 days.This outstanding corrosion resistance was associated with the protective efect of the corrosion products.The increase in the Sn and Ga element content led to the precipitation of a large amount of Mg_(2)Sn and Mg_(5)Ga_(2),which had a dominant efect on the corrosion rate in the Mg-5Sn-1In-2Ga alloy.These precipitates increased the current density and detached from the alloy surface during the corrosion process.This can lead to a weakened protective efect of the corrosion layer,and thus generate localized corrosion and an increase in the corrosion rate.The strength of the Mg-5Sn-1In-2Ga alloy was enhanced due to fne-grain strengthening and precipitation strengthening.The ultimate tensile strength and yield strength of the Mg-5Sn-1In-2Ga alloy were~309 MPa and~253 MPa,respectively.
基金financially supported by the National Natural Science Foundation of China(No.52075391).
文摘The new energy vehicle body composed of multi-metals requires a synchronous chemical conversion coating to exhibit excellent corrosion resistance.Herein,we prepared a titanium/zirconium/water-based oligomeric epoxy silane composite chemical conversion coating on multi-metals,and conducted an investigation into its electrochemical behavior and micro-zone structural characteristics upon immersion in a 3.5%NaCl solution.The electrochemical results combined with characterization results revealed that the corrosion evolution characteristics of the composite coatings could be categorized into three stages of mild corrosion,synergistic protection,and substrate damage.Besides,Si-OH groups interact with Me-OH at the defect on the multi-metal surface to form an organic monolayer coating.This organic monolayer coating,in conjunction with the synergistic inorganic conversion layer comprising Al_(2)O_(3),TiO_(2),2H_(2)O,ZrO_(2),2H_(2)O,effectively cooperates with the corrosion products to hinder the erosion by the corrosive medium and suppresses the progression of the anodic reaction.
