Titanium plates with a Ti−O solid solution surface-hardened layer were cold roll-bonded with 304 stainless steel plates with high work hardening rates.The evolution and mechanisms affecting the interfacial bonding str...Titanium plates with a Ti−O solid solution surface-hardened layer were cold roll-bonded with 304 stainless steel plates with high work hardening rates.The evolution and mechanisms affecting the interfacial bonding strength in titanium/stainless steel laminated composites were investigated.Results indicate that the hardened layer reduces the interfacial bonding strength from over 261 MPa to less than 204 MPa.During the cold roll-bonding process,the hardened layer fractures,leading to the formation of multi-scale cracks that are difficult for the stainless steel to fill.This not only hinders the development of an interlocking interface but also leads to the presence of numerous microcracks and hardened blocks along the nearly straight interface,consequently weakening the interfacial bonding strength.In metals with high work hardening rates,the conventional approach of enhancing interface interlocking and improving interfacial bonding strength by using a surface-hardened layer becomes less effective.展开更多
To enhance the anti-corrosion performance of TC4 alloy across a wide temperature range for modern aircrafts operating in increasingly harsh environments, the (TiB+TiC) hybrid reinforced TC4 composites were prepared by...To enhance the anti-corrosion performance of TC4 alloy across a wide temperature range for modern aircrafts operating in increasingly harsh environments, the (TiB+TiC) hybrid reinforced TC4 composites were prepared by laser melting deposition (LMD) via the in-situ reaction between B_(4)C reinforcement and molten TC4 alloy. The effect of B_(4)C content (0, 0.5, 1.5, wt%) on the microstructure and room/high-temperature corrosion behaviour of the composites was investigated. Microstructural analysis revealed that the microstructure of the composites was significantly influenced by the B_(4)C content. The composite containing 0.5 wt% B_(4)C exhibited an optimal microstructure characterized by refined grains, equiaxed α-Ti transformed from lath-shaped α-Ti, well-distributed (TiB+TiC) phases with a proper amount and reduced pore/dislocation defects. This composite also demonstrated the best corrosion resistance at both room temperature (25 ℃) and high temperature (800 ℃), which was primarily attributed to its comprehensive advantages including a favorable microstructure, a uniform dispersion of thermally stable (TiB+TiC) phases and a stable passivation film.展开更多
Aseries of [(Fe_(0.6)Co_(0.2)Ni_(0.2))_(0.75-0.03x)B_(0.2)Si_(0.05+0.03x)]_(96)Nb_(4) amorphous alloy composite coatings were prepared by adjusting the silicon content(x=0,1,2,3,4,5,and 6)and their microstructures and...Aseries of [(Fe_(0.6)Co_(0.2)Ni_(0.2))_(0.75-0.03x)B_(0.2)Si_(0.05+0.03x)]_(96)Nb_(4) amorphous alloy composite coatings were prepared by adjusting the silicon content(x=0,1,2,3,4,5,and 6)and their microstructures and tribological properties were investigated by laser cladding technique.Additionally,the effect of Si on the glass forming ability(GFA)of the layers was understood.Results show that an appropriate Si content can refine the microstructure of the FeCoNiBSiNb laser cladding layers and improve the mechanical and tribological properties.The hardness of the coating layer increases monotonically with the Si content.At the Si content of 4.8at%(x=0),the coating layer exhibits a relatively low hardness(734.2HV 0.1).Conversely,at the silicon content of 13.44at%(x=3),the coating layer exhibits the highest hardness(1106HV 0.1).The non-crystalline content and tensile strength exhibit an initial increase,followed by a subsequent decrease.At x=2,the coating exhibits its maximum fracture strength(2880 MPa).However,when x>2,the fracture strength of the coating decreases with an increase in x.Conversely,with an increase in Si content,the wear volume loss initially decreases and then increases.At a Si content of 10.56at%(x=2),the coating exhibits the highest non-crystalline content(42%),the highest tensile strength(2880 MPa),and the most favorable dry friction performance.展开更多
Achieving intrinsic strengthening of boron nitride nanosheets(BNNSs)in Ti matrix composites was still an unsettled issue due to its severe and uncontrollable interface reaction.In the present study,high-performance BN...Achieving intrinsic strengthening of boron nitride nanosheets(BNNSs)in Ti matrix composites was still an unsettled issue due to its severe and uncontrollable interface reaction.In the present study,high-performance BNNSs/Ti composites were fabricated by using the warm compaction(WC)technique and rapid heat treatment(HT)strategy on the basis of interfacial nano-TiBw design.The intrinsic structure of BNNSs was well-retained and nano-TiBw on partially reacted BNNSs led to a brilliant interface bond-ing and BNNSs intrinsic strengthening.Tensile tests revealed that 0.1 wt.%BNNSs/Ti composites exhibited the tensile strength(UTS)of 876 MPa(61%higher than pure Ti)and the fracture elongation of 22.6%,demonstrating the well-balanced property.By employing the insitu TEM experiment,we solve an existing debate,uncovering the synergistic toughening effect from BNNSs and interfacial nano-TiBw which effectively inhibited the micro-cracks propagation on BNNSs and heterogeneous interface.This work paves a new way for developing high-performance BNNSs/Ti composites by reaction interface manipulation and underscores the importance of maintaining BNNSs intrinsic structure in the Ti matrix.展开更多
In the field of particle reinforced magnesium(Mg)matrix composites(MMCs),the interfacial microstructures between reinforcements and Mg matrix are a subject of interest for most researchers.In this work,the 2 wt.%Ti pa...In the field of particle reinforced magnesium(Mg)matrix composites(MMCs),the interfacial microstructures between reinforcements and Mg matrix are a subject of interest for most researchers.In this work,the 2 wt.%Ti particle reinforced Mg-6Zn alloy composites with different contents(0,0.5,1,1.5,2 wt.%)of Mn were prepared using semi-solid stirring assisted ultrasonic treatment followed by hot extrusion.With the increment of Mn element,the characteristics of mixed-grain structure became obvious and the DRX was inhibited.Meanwhile,the interfacial product gradually changed from MgZn_(2)to Mn_(2)Ti.The tensile test demonstrated that the 2Ti/Mg-6Zn-1.5Mn composite exhibited an excellent strength-ductility synergy,achieving the highest yield stress(YS),ultimate tensile stress(UTS)of 239 MPa,366 MPa,respectively,along with a notable elongation(El.)of 20.6%.The increased strength is mainly due to the grain refinement,the precipitation strengthening,the HDI strengthening and the strong interfacial bonding including the tightly Ti/Mn_(2)Ti bonding and the Mn_(2)Ti/Mg coherent orientation relationship.The ideal El.is the result of fine/coarse bimodal structure and the proper interfacial reaction,which can reduce the occurrence of cracks.展开更多
In this study,microstructure and mechanical behavior of Mg/Al composite plates with Ti foil interlayer were systematically studied,with a great emphasis on the effect of different thicknesses of Ti foil interlayer.The...In this study,microstructure and mechanical behavior of Mg/Al composite plates with Ti foil interlayer were systematically studied,with a great emphasis on the effect of different thicknesses of Ti foil interlayer.The results show that compared to 100μm thick Ti foil,10μm thick Ti foil is more prone to fracture and is evenly distributed in fragments at the interface.The introduction of Ti foil can effectively refine the grain size of Mg layers of as-rolled Mg/Al composite plates,10μm thick Ti foil has a better refining effect than 100μm thick Ti foil.Ti foil can effectively increase the yield strength(YS)and ultimate strength(UTS)of as-rolled Mg/Al composite plates,10μm thick Ti foil significantly improves the elongation(El)of Mg/Al composite plate,while 100μm thick Ti foil slightly weakens the El.After annealing at 420℃ for 0.5 h and 4 h,Ti foil can inhibit the formation of intermetallic compounds(IMCs)at the interface of Mg/Al composite plates,which effectively improves the YS,UTS and El of Mg/Al composite plates.In addition,Ti foil can also significantly enhance the interfacial shear strength(SS)of Mg/Al composite plates before and after annealing.展开更多
Magnesium matrix composites(MMCs)combine exceptional low density,high specific strength,and stiffness,positioning them as critical materials for aerospace,automotive,and electronics industries.This review highlights r...Magnesium matrix composites(MMCs)combine exceptional low density,high specific strength,and stiffness,positioning them as critical materials for aerospace,automotive,and electronics industries.This review highlights recent progress in the fabrication of Ti-Mg composites and analyzes the mechanisms behind their enhanced mechanical properties.A key focus is the interfacial deformation incompatibility between Ti and Mg phases,which generates strain gradients and promotes the accumulation of geometrically necessary dislocations(GNDs)at the interface.This process not only improves strain hardening and ductility but also reveals the need for advanced micromechanical models to capture the plastic behavior of both phases.The review critically examines the impact of different Mg matrix types(AZ,AM,VW series)and the role of interfacial product morphology and size on bonding and overall performance.Furthermore,Ti reinforcement endows the composites with superior wear resistance and thermal conductivity,indicating broad application potential.展开更多
The Al-Mg_(2)Si in-situ composite is a lightweight material with great potential for application in fields such as automotive lightweighting,aerospace,and electronic components.In this research,the modification,semi-s...The Al-Mg_(2)Si in-situ composite is a lightweight material with great potential for application in fields such as automotive lightweighting,aerospace,and electronic components.In this research,the modification,semi-solid technology coupled with different types of electromagnetic stirring was applied to regulate the undesirable solidified dendritic microstructure and facilitate the composites’mechanical properties.The spheroidization and refinement of Mg_(2)Si andα-Al matrix in SM(semi-solid)+RES(rotate electromagnetic stirring)sample and SM+SHES(single winding helical electromagnetic stirring)sample are realized under the effect of fused dendrite arm,the decreased critical nucleate radius,and the increased nucleation rate and extra supercooling degree induced by electromagnetic stirring.The Mg_(2)Si phase in the SM+RES sample and SM+SHES sample is refined by 73.4%and 75.7%,respectively compared to the AC(as-cast)sample.Besides,the single winding electromagnetic stirring can lead to more homogeneously distributed physical fields,lower temperature gradient,and more significant mass transfer,mainly responsible for the more homogeneous distributed reinforced finer Mg_(2)Si particles in the SM+SHES sample.Moreover,both the tensile properties and hardness of modified semi-solid composites are improved through electromagnetic stirring.Compared with RES,the improvement effect of SHES is more excellent.The SM+SHES sample possesses the highest Brinell hardness(124.7 HB),and its quality index of tensile properties is 5.73%and 82.2%higher than that of the SM+RES and AC samples,respectively.展开更多
There are few studies on the preparation of magnesium matrix composites(MMCs)by rapid solidification.This study aims to add minor amounts of Ti particles to AZ91 alloy and prepare AZ91/Ti_(P) MMC ribbon by Melt-Spinni...There are few studies on the preparation of magnesium matrix composites(MMCs)by rapid solidification.This study aims to add minor amounts of Ti particles to AZ91 alloy and prepare AZ91/Ti_(P) MMC ribbon by Melt-Spinning(MS).The effects of Ti particle content on the microstructure and mechanical properties of AZ91/Ti_(P) ribbon were studied by scanning electron microscopy(SEM),electron backscatter diffraction(EBSD),X-ray diffraction(XRD),transmission electron microscopy(TEM),three-dimensional profiling(3D-P)and calculation of supercooling rate.The results show that the grain refinement of AZ91 ribbon prepared by rapid solidification is very significant and the grain refinement is further improved with the increase of Ti particle content;at the same time,the growth of β-Mg_(17)Al_(12) is inhibited,and the interface reaction between Ti and Mg leads to the formation of interfaces around Ti particles.These nano-scale Ti_(3)Al and Al_(3)Ti interface compounds uniformly wrap the Ti particles.It is believed that the addition of Ti particles not only helps to refine the surrounding grains,but also increases the dislocations in the MMC ribbon and forms a good interface,thereby improving the mechanical properties.Compared with AZ91 alloy ribbon,the yield strength and tensile strength of MMC material containing 5 wt.%Ti particles increased by 25.0%and 22.7% respectively.The elongation only decreased by 10.9%.AZ91/5 wt.%Ti_(P) ribbon has a better balance between high strength and high elongation.The analysis shows that the strengthening effect of this mechanical property is mainly attributed to fine grain strengthening,dislocation strengthening and non-basal slip.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
Titanium/magnesium alloy bimetal composites show promising prospects for lightweight applications.The Ti/Mg bimetal composite was fabricated in Ti−6Al−4V pyramidal lattice structure via AZ91D melt infiltration.Compara...Titanium/magnesium alloy bimetal composites show promising prospects for lightweight applications.The Ti/Mg bimetal composite was fabricated in Ti−6Al−4V pyramidal lattice structure via AZ91D melt infiltration.Comparative analysis of the tensile and compressive properties was conducted between the composite and its constituent materials(Ti−6Al−4V lattice structure and AZ91D matrix).The tensile strength of the composite(95.9 MPa)was comparable to that of the Ti−6Al−4V lattice structure(94.4 MPa)but lower than that of the AZ91D alloy(120.8 MPa)due to gaps at the bimetal interfaces hindering load transfer during tension.The composite exhibited greater elongation(1.7%)compared to AZ91D(1.4%)alloy but less than the Ti−6Al−4V lattice structure(2.6%).The compressive performance of the composite outperformed that of the Ti−6Al−4V lattice structure,underscoring the significance of the AZ91D alloy in compressive deformation.Fracture analysis indicated that the predominant failure reasons in both the composite and lattice structures were attributed to the breakage of lattice struts at nodes caused by the stress concentration.展开更多
The probability of phase formation was predicted using k-nearest neighbor algorithm(KNN)and artificial neural network algorithm(ANN).Additionally,the composition ranges of Ti,Cu,Ni,and Hf in 40 unknown amorphous alloy...The probability of phase formation was predicted using k-nearest neighbor algorithm(KNN)and artificial neural network algorithm(ANN).Additionally,the composition ranges of Ti,Cu,Ni,and Hf in 40 unknown amorphous alloy composites(AACs)were predicted using ANN.The predicted alloys were then experimentally verified through X-ray diffraction(XRD)and high-resolution transmission electron microscopy(HRTEM).The prediction accuracies of the ANN for AM and IM phases are 93.12%and 85.16%,respectively,while the prediction accuracies of KNN for AM and IM phases are 93%and 84%,respectively.It is observed that when the contents of Ti,Cu,Ni,and Hf fall within the ranges of 32.7−34.5 at.%,16.4−17.3 at.%,30.9−32.7 at.%,and 17.3−18.3 at.%,respectively,it is more likely to form AACs.Based on the results of XRD and HRTEM,the Ti_(34)Cu17Ni_(31.36)Hf_(17.64)and Ti_(36)Cu_(18)Ni_(29.44)Hf_(16.56)alloys are identified as good AACs,which are in closely consistent with the predicted amorphous alloy compositions.展开更多
A Y2O3 particle enhanced Ni/TiC composite coating was fabricated in-situ on a TC4 Ti alloy by laser surface cladding.The phase component,microstructure,composition distribution and properties of the composite layer we...A Y2O3 particle enhanced Ni/TiC composite coating was fabricated in-situ on a TC4 Ti alloy by laser surface cladding.The phase component,microstructure,composition distribution and properties of the composite layer were investigated.The composite layer has graded microstructures and compositions,due to the fast melting followed by rapid solidification and cooling during laser cladding.The TiC powders are completely dissolved into the melted layer during melting and segregated as fine dendrites when solidified.The size of TiC dendrites decreases with increasing depth.Y2O3 fine particles distribute in the whole clad layer.The Y2O3 particle enhanced Ni/TiC composite layer has a quite uniform hardness along depth with a maximum value of HV1380,which is 4 times higher than the initial hardness.The wear resistance of the Ti alloy is significantly improved after laser cladding due to the high hardness of the composite coating.展开更多
AZ31-4.6% Mg2Si （mass fraction） composite was prepared by conventional casting method. Repetitive upsetting （RU） was applied to severely deforming the as-cast composite at 400 ℃ for 1, 3, and 5 passes. Finite ele...AZ31-4.6% Mg2Si （mass fraction） composite was prepared by conventional casting method. Repetitive upsetting （RU） was applied to severely deforming the as-cast composite at 400 ℃ for 1, 3, and 5 passes. Finite element analysis of the material flow indicates that deformation concentrates in the bottom region of the sample after 1 pass, and much more uniform deformation is obtained after 5 passes. During multi-pass RU process, both dendritic and Chinese script type Mg2Si phases are broken up into smaller particles owing to the shear stress forced by the matrix. With the increasing number of RU passes, finer grain size and more homogeneous distribution of Mg2Si particles are obtained along with significant enhancement in both strength and ductility. AZ31-4.6%Mg2Si composite exhibits tensile strength of 284 MPa and elongation of 9.8%after 5 RU passes at 400 ℃ compared with the initial 128 MPa and 5.4%of original AZ31-4.6%Mg2Si composite.展开更多
The Al/Si/SiC composites with medium volume fraction for electronic packaging were fabricated by gas pressure infiltration.On the premise of keeping the machinability of the composites,the silicon carbide particles,wh...The Al/Si/SiC composites with medium volume fraction for electronic packaging were fabricated by gas pressure infiltration.On the premise of keeping the machinability of the composites,the silicon carbide particles,which have the similar size with silicon particles（average 13 μm）,were added to replace silicon particles of same volume fraction,and microstructure and properties of the composites were investigated.The results show that reinforcing particles are distributed uniformly and no apparent pores are observed in the composites.It is also observed that higher thermal conductivity（TC） and flexural strength will be obtained with the addition of SiC particles.Meanwhile,coefficient of thermal expansion（CTE） changes smaller than TC.Models for predicting thermal properties were also discussed.Equivalent effective conductivity（EEC） was proposed to make H-J model suitable for hybrid particles and multimodal particle size distribution.展开更多
The influence of solution treatment on the microstructure and properties of Mg2Si/AZ91D composites fabricated from Mg-SiO2 system via in-situ processing method was investigated.The results show that coarse Chinese scr...The influence of solution treatment on the microstructure and properties of Mg2Si/AZ91D composites fabricated from Mg-SiO2 system via in-situ processing method was investigated.The results show that coarse Chinese script shape Mg2Si phases can be formed by adding SiO2 into AZ91D magnesium alloy with Si content up to 1.5% of the alloy melt.During solution treatment,the morphology and distribution of the coarse Chinese script shape Mg2Si phases are modified.Meanwhile,the β-Mg17Al12 phase is dissolved into the magnesium matrix.With increasing holding time,the coarse Mg2Si phases tend to dissolve,break and spheroidize.After solution treatment at 420 ℃ for 16 h,Mg2Si phases become the finest and relatively well-distributed phase.The tensile strength and elongation are increased by 14.9% and 38.9%,respectively.It is believed that the Mg2Si phases continuously dissolve and break,and finally the spheroidized Mg2Si particles are obtained due to the interface tension of Mg2Si/Mg interface.展开更多
Microstructures of Ti2AlN/TiAl composites prepared by in-situ method were characterized in in-situ and aging treatment conditions and the nitride precipitation was investigated in Ti2AlN/TiAl composites aged at 900 ℃...Microstructures of Ti2AlN/TiAl composites prepared by in-situ method were characterized in in-situ and aging treatment conditions and the nitride precipitation was investigated in Ti2AlN/TiAl composites aged at 900 ℃ for 24 h after being heat treated at 1400 ℃ for 0.5 h. The in-situ composites consist of γ＋α2 lamellar colonies, equiaxed y grains and Ti2AlN reinforcements. Matrix with nearly fully lamellar structure formed after solution and subsequently aging treatment. With the increase of Ti2AlN content, the nearly fully lamellar structure becomes instable for the aged composites. According to TEM study, fine Ti2AlN precipitates are found to distribute at the grain boundaries of lamellar colony. Needle-like Ti3AlN precipitates arrange in line with growing axis parallel to [001] direction of the γ-TiAl matrix and another needle-like Ti3AlN precipitates with lager size distribute at the dislocations. Key words：展开更多
TiB2/Al-30Si composites were fabricated via in-situ melt reaction under high-energy ultrasonic field. The microstructure and wear properties of the composite were investigated by XRD, SEM and dry sliding testing. The ...TiB2/Al-30Si composites were fabricated via in-situ melt reaction under high-energy ultrasonic field. The microstructure and wear properties of the composite were investigated by XRD, SEM and dry sliding testing. The results indicate that TiB2 reinforcement particles are uniformly distributed in the aluminum matrix under high-energy ultrasonic field. The morphology of the TiB2 particles is in circle-shape or quadrangle-shape, and the size of the particles is 0.1-1.5μm. The primary silicon particles are in quadrangle-shape and the average size of them is about 10μm. Hardness values of the Al-30Si matrix alloy and the TiB2/Al-30Si composites considerably increase as the high energy ultrasonic power increases. In particular, the maximum hardness value of the in-situ composites is about 1.3 times as high as that of the matrix alloy when the ultrasonic power is 1.2 kW, reaching 412 MPa. Meanwhile, the wear resistance of the in-situ TiB2/Al-30Si composites prepared under high-energy ultrasonic field is obviously improved and is insensitive to the applied loads of the dry sliding testing.展开更多
Microstructure stability of in situ synthesized Ti2AlN/Ti-48Al-2Cr-2Nb composite during aging at 900 ℃ was investigated by XRD, OM and TEM, and the unreinforced Ti-48Al-2Cr-2Nb alloy was also examined for comparison....Microstructure stability of in situ synthesized Ti2AlN/Ti-48Al-2Cr-2Nb composite during aging at 900 ℃ was investigated by XRD, OM and TEM, and the unreinforced Ti-48Al-2Cr-2Nb alloy was also examined for comparison. The result showed that in the TiAl alloy,α2 lamellae thinned and were broken down, and became discontinuous with increasing aging time. The decomposition ofα2 lamella toγ which was characterized by parallel decomposition and breakdown ofα2 lamellae led to the degradation of the lamellar structure. While in the composite, lamellar structure remained relatively stable even after aging at 900 ℃ for 100 h. No breakdown ofα2 lamellae except parallel decomposition and precipitation of fine nitride particles was observed. The better microstructural stability of the composite was mainly attributed to the precipitation of Ti2AlN particles at theα2/γ interface which played an important role in retarding the coarsening of lamellar microstructure in the matrix of composite.展开更多
The friction and wear behavior of magnesium matrix composites reinforced with particulate Mg2Si was characterized. The influence of Si, applied load and sliding rate on the wear behavior of Mg2Si/AM60 magnesium matrix...The friction and wear behavior of magnesium matrix composites reinforced with particulate Mg2Si was characterized. The influence of Si, applied load and sliding rate on the wear behavior of Mg2Si/AM60 magnesium matrix composites was studied. The results indicate that the particulate Mg2Si can be synthesized by adding Si into magnesium alloy. The wear properties of AM60 magnesium alloy are significantly improved with MgzSi particles. The wear mass losses of AM60 magnesium alloy and MgaSi/AM60 magnesium matrix composites decrease with increase in applied load and sliding rate. The wear feature of the AM60 magnesium alloy is adhesion wear. The wear mechanism of Mg2Si/AM60 magnesium matrix composites transforms from abrasive wear to adhesion wear with the increase of load.展开更多
基金supported by the National Key R&D Program of China (No. 2018YFA0707300)the National Natural Science Foundation of China (No. 52374376)the Introduction Plan for High end Foreign Experts, China (No. G2023105001L)。
文摘Titanium plates with a Ti−O solid solution surface-hardened layer were cold roll-bonded with 304 stainless steel plates with high work hardening rates.The evolution and mechanisms affecting the interfacial bonding strength in titanium/stainless steel laminated composites were investigated.Results indicate that the hardened layer reduces the interfacial bonding strength from over 261 MPa to less than 204 MPa.During the cold roll-bonding process,the hardened layer fractures,leading to the formation of multi-scale cracks that are difficult for the stainless steel to fill.This not only hinders the development of an interlocking interface but also leads to the presence of numerous microcracks and hardened blocks along the nearly straight interface,consequently weakening the interfacial bonding strength.In metals with high work hardening rates,the conventional approach of enhancing interface interlocking and improving interfacial bonding strength by using a surface-hardened layer becomes less effective.
基金supported by the Tianjin Municipal Natural Science Foundation(No.23JCYBJC00040)the National Nat-ural Science Foundation of China(No.52175369)the Tian-jin Research Innovation Project for Postgraduate Students(No.2022SKY134).
文摘To enhance the anti-corrosion performance of TC4 alloy across a wide temperature range for modern aircrafts operating in increasingly harsh environments, the (TiB+TiC) hybrid reinforced TC4 composites were prepared by laser melting deposition (LMD) via the in-situ reaction between B_(4)C reinforcement and molten TC4 alloy. The effect of B_(4)C content (0, 0.5, 1.5, wt%) on the microstructure and room/high-temperature corrosion behaviour of the composites was investigated. Microstructural analysis revealed that the microstructure of the composites was significantly influenced by the B_(4)C content. The composite containing 0.5 wt% B_(4)C exhibited an optimal microstructure characterized by refined grains, equiaxed α-Ti transformed from lath-shaped α-Ti, well-distributed (TiB+TiC) phases with a proper amount and reduced pore/dislocation defects. This composite also demonstrated the best corrosion resistance at both room temperature (25 ℃) and high temperature (800 ℃), which was primarily attributed to its comprehensive advantages including a favorable microstructure, a uniform dispersion of thermally stable (TiB+TiC) phases and a stable passivation film.
文摘Aseries of [(Fe_(0.6)Co_(0.2)Ni_(0.2))_(0.75-0.03x)B_(0.2)Si_(0.05+0.03x)]_(96)Nb_(4) amorphous alloy composite coatings were prepared by adjusting the silicon content(x=0,1,2,3,4,5,and 6)and their microstructures and tribological properties were investigated by laser cladding technique.Additionally,the effect of Si on the glass forming ability(GFA)of the layers was understood.Results show that an appropriate Si content can refine the microstructure of the FeCoNiBSiNb laser cladding layers and improve the mechanical and tribological properties.The hardness of the coating layer increases monotonically with the Si content.At the Si content of 4.8at%(x=0),the coating layer exhibits a relatively low hardness(734.2HV 0.1).Conversely,at the silicon content of 13.44at%(x=3),the coating layer exhibits the highest hardness(1106HV 0.1).The non-crystalline content and tensile strength exhibit an initial increase,followed by a subsequent decrease.At x=2,the coating exhibits its maximum fracture strength(2880 MPa).However,when x>2,the fracture strength of the coating decreases with an increase in x.Conversely,with an increase in Si content,the wear volume loss initially decreases and then increases.At a Si content of 10.56at%(x=2),the coating exhibits the highest non-crystalline content(42%),the highest tensile strength(2880 MPa),and the most favorable dry friction performance.
基金the National Natural Science Foundation of China(No.52301186)the Fundamental Research Funds for the Central Universitiesthe Young Elite Scientists Sponsorship Program by CAST(Grant No.2022QNRC001).
文摘Achieving intrinsic strengthening of boron nitride nanosheets(BNNSs)in Ti matrix composites was still an unsettled issue due to its severe and uncontrollable interface reaction.In the present study,high-performance BNNSs/Ti composites were fabricated by using the warm compaction(WC)technique and rapid heat treatment(HT)strategy on the basis of interfacial nano-TiBw design.The intrinsic structure of BNNSs was well-retained and nano-TiBw on partially reacted BNNSs led to a brilliant interface bond-ing and BNNSs intrinsic strengthening.Tensile tests revealed that 0.1 wt.%BNNSs/Ti composites exhibited the tensile strength(UTS)of 876 MPa(61%higher than pure Ti)and the fracture elongation of 22.6%,demonstrating the well-balanced property.By employing the insitu TEM experiment,we solve an existing debate,uncovering the synergistic toughening effect from BNNSs and interfacial nano-TiBw which effectively inhibited the micro-cracks propagation on BNNSs and heterogeneous interface.This work paves a new way for developing high-performance BNNSs/Ti composites by reaction interface manipulation and underscores the importance of maintaining BNNSs intrinsic structure in the Ti matrix.
基金the Guangdong Major Project of Basic and Applied Basic Research(2020B0301030006)National Natural Science Foundation of China(52225101 and 52101123)+2 种基金Fundamental Research Funds for the Central Universities(2023CDJYXTD-002)Support Program for Overseas Educated Students Returning to China for Entrepreneurship and Innovation(cx2023020)Chongqing Natural Science Foundation of China(CSTB2023NSCQ-MSX0571).
文摘In the field of particle reinforced magnesium(Mg)matrix composites(MMCs),the interfacial microstructures between reinforcements and Mg matrix are a subject of interest for most researchers.In this work,the 2 wt.%Ti particle reinforced Mg-6Zn alloy composites with different contents(0,0.5,1,1.5,2 wt.%)of Mn were prepared using semi-solid stirring assisted ultrasonic treatment followed by hot extrusion.With the increment of Mn element,the characteristics of mixed-grain structure became obvious and the DRX was inhibited.Meanwhile,the interfacial product gradually changed from MgZn_(2)to Mn_(2)Ti.The tensile test demonstrated that the 2Ti/Mg-6Zn-1.5Mn composite exhibited an excellent strength-ductility synergy,achieving the highest yield stress(YS),ultimate tensile stress(UTS)of 239 MPa,366 MPa,respectively,along with a notable elongation(El.)of 20.6%.The increased strength is mainly due to the grain refinement,the precipitation strengthening,the HDI strengthening and the strong interfacial bonding including the tightly Ti/Mn_(2)Ti bonding and the Mn_(2)Ti/Mg coherent orientation relationship.The ideal El.is the result of fine/coarse bimodal structure and the proper interfacial reaction,which can reduce the occurrence of cracks.
基金supported by the National Key Research and Development Program of China(2022YFB3708400)the Guangdong Major Project of Basic and Applied Basic Research(2020B0301030006)+4 种基金the Youth Talent Support Programme of Guangdong Provincial Association for Science and Technology(SKXRC202301)the Guangdong Academy of Science Fund(2020GDASYL-20200101001,2023GDASQNRC-0210,2023GDASQNRC-0321)the Guangdong Science and Technology plan project(2023A0505030002)the GINM’Special Project of Science and Technology Development(2023GINMZX-202301020108)Evaluation Project of Guangdong Provincial Key Laboratory(2023B1212060043).
文摘In this study,microstructure and mechanical behavior of Mg/Al composite plates with Ti foil interlayer were systematically studied,with a great emphasis on the effect of different thicknesses of Ti foil interlayer.The results show that compared to 100μm thick Ti foil,10μm thick Ti foil is more prone to fracture and is evenly distributed in fragments at the interface.The introduction of Ti foil can effectively refine the grain size of Mg layers of as-rolled Mg/Al composite plates,10μm thick Ti foil has a better refining effect than 100μm thick Ti foil.Ti foil can effectively increase the yield strength(YS)and ultimate strength(UTS)of as-rolled Mg/Al composite plates,10μm thick Ti foil significantly improves the elongation(El)of Mg/Al composite plate,while 100μm thick Ti foil slightly weakens the El.After annealing at 420℃ for 0.5 h and 4 h,Ti foil can inhibit the formation of intermetallic compounds(IMCs)at the interface of Mg/Al composite plates,which effectively improves the YS,UTS and El of Mg/Al composite plates.In addition,Ti foil can also significantly enhance the interfacial shear strength(SS)of Mg/Al composite plates before and after annealing.
基金the financial support from the National Key R&D Program of China(No.2022YFB3708400)National Natural Science Foundation of China(No.52171133,52225101)Basic and Applied Basic Research Foundation of Guangdong(No.2020B0301030006)。
文摘Magnesium matrix composites(MMCs)combine exceptional low density,high specific strength,and stiffness,positioning them as critical materials for aerospace,automotive,and electronics industries.This review highlights recent progress in the fabrication of Ti-Mg composites and analyzes the mechanisms behind their enhanced mechanical properties.A key focus is the interfacial deformation incompatibility between Ti and Mg phases,which generates strain gradients and promotes the accumulation of geometrically necessary dislocations(GNDs)at the interface.This process not only improves strain hardening and ductility but also reveals the need for advanced micromechanical models to capture the plastic behavior of both phases.The review critically examines the impact of different Mg matrix types(AZ,AM,VW series)and the role of interfacial product morphology and size on bonding and overall performance.Furthermore,Ti reinforcement endows the composites with superior wear resistance and thermal conductivity,indicating broad application potential.
基金supported by the National Key R&D Projects(No.2021YFB3702000)the Institute Projects of Ansteel Beijing Research Institute(No.2023BJC-06)the Regional Company Projects in Ansteel Beijing Research Institute(No.2022BJB-18BG&No.2022BJB-13GF).
文摘The Al-Mg_(2)Si in-situ composite is a lightweight material with great potential for application in fields such as automotive lightweighting,aerospace,and electronic components.In this research,the modification,semi-solid technology coupled with different types of electromagnetic stirring was applied to regulate the undesirable solidified dendritic microstructure and facilitate the composites’mechanical properties.The spheroidization and refinement of Mg_(2)Si andα-Al matrix in SM(semi-solid)+RES(rotate electromagnetic stirring)sample and SM+SHES(single winding helical electromagnetic stirring)sample are realized under the effect of fused dendrite arm,the decreased critical nucleate radius,and the increased nucleation rate and extra supercooling degree induced by electromagnetic stirring.The Mg_(2)Si phase in the SM+RES sample and SM+SHES sample is refined by 73.4%and 75.7%,respectively compared to the AC(as-cast)sample.Besides,the single winding electromagnetic stirring can lead to more homogeneously distributed physical fields,lower temperature gradient,and more significant mass transfer,mainly responsible for the more homogeneous distributed reinforced finer Mg_(2)Si particles in the SM+SHES sample.Moreover,both the tensile properties and hardness of modified semi-solid composites are improved through electromagnetic stirring.Compared with RES,the improvement effect of SHES is more excellent.The SM+SHES sample possesses the highest Brinell hardness(124.7 HB),and its quality index of tensile properties is 5.73%and 82.2%higher than that of the SM+RES and AC samples,respectively.
基金supported by the National Key Research and Development Program of China(2022YFB3708400)the Guangdong Major Project of Basic and Applied Basic Research(2020B0301030006)+1 种基金the Guangdong Academy of Science Fund(2020GDASYL-20200101001)Evaluation Project of Guangdong Provincial Key Laboratory(2023B1212060043).
文摘There are few studies on the preparation of magnesium matrix composites(MMCs)by rapid solidification.This study aims to add minor amounts of Ti particles to AZ91 alloy and prepare AZ91/Ti_(P) MMC ribbon by Melt-Spinning(MS).The effects of Ti particle content on the microstructure and mechanical properties of AZ91/Ti_(P) ribbon were studied by scanning electron microscopy(SEM),electron backscatter diffraction(EBSD),X-ray diffraction(XRD),transmission electron microscopy(TEM),three-dimensional profiling(3D-P)and calculation of supercooling rate.The results show that the grain refinement of AZ91 ribbon prepared by rapid solidification is very significant and the grain refinement is further improved with the increase of Ti particle content;at the same time,the growth of β-Mg_(17)Al_(12) is inhibited,and the interface reaction between Ti and Mg leads to the formation of interfaces around Ti particles.These nano-scale Ti_(3)Al and Al_(3)Ti interface compounds uniformly wrap the Ti particles.It is believed that the addition of Ti particles not only helps to refine the surrounding grains,but also increases the dislocations in the MMC ribbon and forms a good interface,thereby improving the mechanical properties.Compared with AZ91 alloy ribbon,the yield strength and tensile strength of MMC material containing 5 wt.%Ti particles increased by 25.0%and 22.7% respectively.The elongation only decreased by 10.9%.AZ91/5 wt.%Ti_(P) ribbon has a better balance between high strength and high elongation.The analysis shows that the strengthening effect of this mechanical property is mainly attributed to fine grain strengthening,dislocation strengthening and non-basal slip.
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.
基金the financial support from the National Natural Science Foundation of China(Nos.51875062,52205336)。
文摘Titanium/magnesium alloy bimetal composites show promising prospects for lightweight applications.The Ti/Mg bimetal composite was fabricated in Ti−6Al−4V pyramidal lattice structure via AZ91D melt infiltration.Comparative analysis of the tensile and compressive properties was conducted between the composite and its constituent materials(Ti−6Al−4V lattice structure and AZ91D matrix).The tensile strength of the composite(95.9 MPa)was comparable to that of the Ti−6Al−4V lattice structure(94.4 MPa)but lower than that of the AZ91D alloy(120.8 MPa)due to gaps at the bimetal interfaces hindering load transfer during tension.The composite exhibited greater elongation(1.7%)compared to AZ91D(1.4%)alloy but less than the Ti−6Al−4V lattice structure(2.6%).The compressive performance of the composite outperformed that of the Ti−6Al−4V lattice structure,underscoring the significance of the AZ91D alloy in compressive deformation.Fracture analysis indicated that the predominant failure reasons in both the composite and lattice structures were attributed to the breakage of lattice struts at nodes caused by the stress concentration.
基金supported by the National Natural Science Foundation of China(No.51601019)the Guangdong Basic and Applied Basic Research Foundation,China(No.2022A1515010233)+1 种基金the Key Project of Shaanxi Province of Qinchuangyuan“Scientist and Engineer”Team Construction,China(No.2023KXJ-123)the Natural Science Foundation of Shaanxi Province,China(No.2024JC-YBMS-014).
文摘The probability of phase formation was predicted using k-nearest neighbor algorithm(KNN)and artificial neural network algorithm(ANN).Additionally,the composition ranges of Ti,Cu,Ni,and Hf in 40 unknown amorphous alloy composites(AACs)were predicted using ANN.The predicted alloys were then experimentally verified through X-ray diffraction(XRD)and high-resolution transmission electron microscopy(HRTEM).The prediction accuracies of the ANN for AM and IM phases are 93.12%and 85.16%,respectively,while the prediction accuracies of KNN for AM and IM phases are 93%and 84%,respectively.It is observed that when the contents of Ti,Cu,Ni,and Hf fall within the ranges of 32.7−34.5 at.%,16.4−17.3 at.%,30.9−32.7 at.%,and 17.3−18.3 at.%,respectively,it is more likely to form AACs.Based on the results of XRD and HRTEM,the Ti_(34)Cu17Ni_(31.36)Hf_(17.64)and Ti_(36)Cu_(18)Ni_(29.44)Hf_(16.56)alloys are identified as good AACs,which are in closely consistent with the predicted amorphous alloy compositions.
基金Projects(51101096,51002093)supported by the National Natural Science Foundation of ChinaProject(1052nm05000)supported by Special Foundation of the Shanghai Science and Technology Commission for Nano-Materials ResearchProject(J51042)supported by Leading Academic Discipline Project of the Shanghai Education Commission,China
文摘A Y2O3 particle enhanced Ni/TiC composite coating was fabricated in-situ on a TC4 Ti alloy by laser surface cladding.The phase component,microstructure,composition distribution and properties of the composite layer were investigated.The composite layer has graded microstructures and compositions,due to the fast melting followed by rapid solidification and cooling during laser cladding.The TiC powders are completely dissolved into the melted layer during melting and segregated as fine dendrites when solidified.The size of TiC dendrites decreases with increasing depth.Y2O3 fine particles distribute in the whole clad layer.The Y2O3 particle enhanced Ni/TiC composite layer has a quite uniform hardness along depth with a maximum value of HV1380,which is 4 times higher than the initial hardness.The wear resistance of the Ti alloy is significantly improved after laser cladding due to the high hardness of the composite coating.
基金Projects(51074106,51374145)supported by the National Natural Science Foundation of ChinaProject(09JC1408200)supported by the Science and Technology Commission of Shanghai Municipality,China+1 种基金Project(2014M561466)supported by China Postdoctoral Science FoundationProject(14R21411000)supported by Shanghai Postdoctoral Scientific Program,China
文摘AZ31-4.6% Mg2Si （mass fraction） composite was prepared by conventional casting method. Repetitive upsetting （RU） was applied to severely deforming the as-cast composite at 400 ℃ for 1, 3, and 5 passes. Finite element analysis of the material flow indicates that deformation concentrates in the bottom region of the sample after 1 pass, and much more uniform deformation is obtained after 5 passes. During multi-pass RU process, both dendritic and Chinese script type Mg2Si phases are broken up into smaller particles owing to the shear stress forced by the matrix. With the increasing number of RU passes, finer grain size and more homogeneous distribution of Mg2Si particles are obtained along with significant enhancement in both strength and ductility. AZ31-4.6%Mg2Si composite exhibits tensile strength of 284 MPa and elongation of 9.8%after 5 RU passes at 400 ℃ compared with the initial 128 MPa and 5.4%of original AZ31-4.6%Mg2Si composite.
基金Project (60776019) supported by the National Natural Science Foundation of ChinaProject (61-TP-2010) supported by the Research Fund of the State Key Laboratory of Solidification Processing (NWPU),China
文摘The Al/Si/SiC composites with medium volume fraction for electronic packaging were fabricated by gas pressure infiltration.On the premise of keeping the machinability of the composites,the silicon carbide particles,which have the similar size with silicon particles（average 13 μm）,were added to replace silicon particles of same volume fraction,and microstructure and properties of the composites were investigated.The results show that reinforcing particles are distributed uniformly and no apparent pores are observed in the composites.It is also observed that higher thermal conductivity（TC） and flexural strength will be obtained with the addition of SiC particles.Meanwhile,coefficient of thermal expansion（CTE） changes smaller than TC.Models for predicting thermal properties were also discussed.Equivalent effective conductivity（EEC） was proposed to make H-J model suitable for hybrid particles and multimodal particle size distribution.
基金Project (BG2007030) supported by High-tech Research Program of Jiangsu Province, ChinaProject (07KJA43008) supported by the Natural Science Foundation of Jiangsu Province, ChinaProject (20070299004) supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China
文摘The influence of solution treatment on the microstructure and properties of Mg2Si/AZ91D composites fabricated from Mg-SiO2 system via in-situ processing method was investigated.The results show that coarse Chinese script shape Mg2Si phases can be formed by adding SiO2 into AZ91D magnesium alloy with Si content up to 1.5% of the alloy melt.During solution treatment,the morphology and distribution of the coarse Chinese script shape Mg2Si phases are modified.Meanwhile,the β-Mg17Al12 phase is dissolved into the magnesium matrix.With increasing holding time,the coarse Mg2Si phases tend to dissolve,break and spheroidize.After solution treatment at 420 ℃ for 16 h,Mg2Si phases become the finest and relatively well-distributed phase.The tensile strength and elongation are increased by 14.9% and 38.9%,respectively.It is believed that the Mg2Si phases continuously dissolve and break,and finally the spheroidized Mg2Si particles are obtained due to the interface tension of Mg2Si/Mg interface.
基金Project(2011CB605502)supported by the National Basic Research Program of ChinaProject(51001086)supported by the National Natural Science Foundation of China
文摘Microstructures of Ti2AlN/TiAl composites prepared by in-situ method were characterized in in-situ and aging treatment conditions and the nitride precipitation was investigated in Ti2AlN/TiAl composites aged at 900 ℃ for 24 h after being heat treated at 1400 ℃ for 0.5 h. The in-situ composites consist of γ＋α2 lamellar colonies, equiaxed y grains and Ti2AlN reinforcements. Matrix with nearly fully lamellar structure formed after solution and subsequently aging treatment. With the increase of Ti2AlN content, the nearly fully lamellar structure becomes instable for the aged composites. According to TEM study, fine Ti2AlN precipitates are found to distribute at the grain boundaries of lamellar colony. Needle-like Ti3AlN precipitates arrange in line with growing axis parallel to [001] direction of the γ-TiAl matrix and another needle-like Ti3AlN precipitates with lager size distribute at the dislocations. Key words：
基金Project(51174098)supported by the National Natural Science Foundation of ChinaProject(kjsmcx0903)supported by the Foundation of the Jiangsu Province Key Laboratory of Materials Tribology,China+2 种基金Project(1202015B)supported by the Postdoctoral Science Foundation of Jiangsu Province,ChinaProject(03)supported by the Undergraduate Practice-Innovation Training Foundation of Jiangsu University,ChinaProjects(GY2012020,GY2013032)supported by the Science and Technology Support Plan Project Foundation of Zhenjiang City,China
文摘TiB2/Al-30Si composites were fabricated via in-situ melt reaction under high-energy ultrasonic field. The microstructure and wear properties of the composite were investigated by XRD, SEM and dry sliding testing. The results indicate that TiB2 reinforcement particles are uniformly distributed in the aluminum matrix under high-energy ultrasonic field. The morphology of the TiB2 particles is in circle-shape or quadrangle-shape, and the size of the particles is 0.1-1.5μm. The primary silicon particles are in quadrangle-shape and the average size of them is about 10μm. Hardness values of the Al-30Si matrix alloy and the TiB2/Al-30Si composites considerably increase as the high energy ultrasonic power increases. In particular, the maximum hardness value of the in-situ composites is about 1.3 times as high as that of the matrix alloy when the ultrasonic power is 1.2 kW, reaching 412 MPa. Meanwhile, the wear resistance of the in-situ TiB2/Al-30Si composites prepared under high-energy ultrasonic field is obviously improved and is insensitive to the applied loads of the dry sliding testing.
基金Project(2011CB605502)supported by the National Basic Research Program of ChinaProject(B08040)supported by Introducing Talents of Discipline to Universities,China
文摘Microstructure stability of in situ synthesized Ti2AlN/Ti-48Al-2Cr-2Nb composite during aging at 900 ℃ was investigated by XRD, OM and TEM, and the unreinforced Ti-48Al-2Cr-2Nb alloy was also examined for comparison. The result showed that in the TiAl alloy,α2 lamellae thinned and were broken down, and became discontinuous with increasing aging time. The decomposition ofα2 lamella toγ which was characterized by parallel decomposition and breakdown ofα2 lamellae led to the degradation of the lamellar structure. While in the composite, lamellar structure remained relatively stable even after aging at 900 ℃ for 100 h. No breakdown ofα2 lamellae except parallel decomposition and precipitation of fine nitride particles was observed. The better microstructural stability of the composite was mainly attributed to the precipitation of Ti2AlN particles at theα2/γ interface which played an important role in retarding the coarsening of lamellar microstructure in the matrix of composite.
基金Project supported by the Key Laboratory of Ministry of Education for Conveyance and Equipment (East China Jiaotong University), ChinaProject (GJJ11094) supported by Science Funds of Jiangxi Provincial Education Project on Department, China
文摘The friction and wear behavior of magnesium matrix composites reinforced with particulate Mg2Si was characterized. The influence of Si, applied load and sliding rate on the wear behavior of Mg2Si/AM60 magnesium matrix composites was studied. The results indicate that the particulate Mg2Si can be synthesized by adding Si into magnesium alloy. The wear properties of AM60 magnesium alloy are significantly improved with MgzSi particles. The wear mass losses of AM60 magnesium alloy and MgaSi/AM60 magnesium matrix composites decrease with increase in applied load and sliding rate. The wear feature of the AM60 magnesium alloy is adhesion wear. The wear mechanism of Mg2Si/AM60 magnesium matrix composites transforms from abrasive wear to adhesion wear with the increase of load.
