MgO-CaO(40 wt.%CaO)refractory aggregates were prepared using the calcined dolomite and light-burned magnesia fine powder as raw materials and TiO_(2) as additive.The effect of TiO_(2) on their phase composition,micros...MgO-CaO(40 wt.%CaO)refractory aggregates were prepared using the calcined dolomite and light-burned magnesia fine powder as raw materials and TiO_(2) as additive.The effect of TiO_(2) on their phase composition,microstructures and properties was investigated by X-ray diffraction and scanning electron microscopy.The properties such as bulk density,apparent porosity,relative aggregate tube strength and hydration resistance were also investigated.The results showed that the CaTiO_(3) generated by the reaction between CaO and TiO_(2) was distributed around the CaO grain boundaries and intermittently distributed with MgO,which formed an isolation layer around CaO and greatly improved the hydration resistance.Meanwhile,the introduction of TiO_(2) promoted sintering and increased the grain size,further improving the strengths and hydration resistance of the materials.In addition,the most significant enhancement in the hydration resistance and strengths of the samples was achieved when 1.0-2.0 wt.%TiO_(2) was added.In this case,the relative strength of aggregate increased from 33.3% to 37.3%-43.1%,and the mass gain after the hydration test decreased from 3.13% to 1.26%-1.45%.展开更多
The interaction of MgO-MgAl_(2)O_(4)-based and MgO-Cr_(2)O_(3)-based refractories with X70 molten steel was studied by immersion experiments at 1560℃.The effects of immersion time(30 and 60 min)on the contents of tot...The interaction of MgO-MgAl_(2)O_(4)-based and MgO-Cr_(2)O_(3)-based refractories with X70 molten steel was studied by immersion experiments at 1560℃.The effects of immersion time(30 and 60 min)on the contents of total oxygen(TO),Al,Nb,Si,Mn,and Cr as well as the composition,number density,and size distribution of inclusions in the molten steel were investigated.The influence of the penetration and erosion degree of the molten steel to the refractory on the steel-refractory interface layer was analyzed.The results show that,at 1560℃,the MgO-MgAl_(2)O_(4)-based refractory can better control the contents of TO and the composition of molten steel compared with the MgO-Cr_(2)O_(3)-based refractory.The TO content is only 16×10^(-4) wt.%in the molten steel after reacted with the Mg0-MgAl_(2)O_(4)-based refractory at the end point of refining,4 accounting for 11.5%of that reacted with the MgO-Cr_(2)O_(3)-based refractory(139×10^(-4) wt.%).The number density of inclusions is only 14 mm^(-2),and the average size ofinclusions is only 1.31μm,with thelargest proportion of inclusions in 1-2μm(70%).The Al_(2)O_(3)-MnS-CaO complex inclusions in the original steel changed to complex inclusions dominated by Cr-Nb-Mn-S-O and MgO.Al_(2)O_(3),corresponding to the MgO-Cr_(2)O_(3)-based and MgO-MgAl_(2)O_(4)-based refractories,respectively.The MgO.Al_(2)O_(3) layer was formed at the reaction interface between MgO-MgAl_(2)O_(4)-based refractory and molten steel,which is helpful to restrict the erosion of refractories and the pollution of molten steel.The damage mechanism of the MgO-Cr_(2)O_(3)-based refractory is mainly permeation and chemical reaction,while the damage of the MgO-MgAl_(2)O_(4)-based refractory is mainlyscouring erosion.展开更多
Refractory high/medium-entropy alloys(RH/MEAs)are known for their outstanding performance at el-evated temperatures;however,they usually exhibit poor room-temperature plasticity,which can be at-tributed to the non-uni...Refractory high/medium-entropy alloys(RH/MEAs)are known for their outstanding performance at el-evated temperatures;however,they usually exhibit poor room-temperature plasticity,which can be at-tributed to the non-uniform deformation that occurs at room temperature.Once cracks nucleate,they will rapidly propagate into vertical splitting cracks.Here,we introduce multiple phases including FCC and HCP phases into the NbMoTa RMEA via appropriate addition of carbon.The results show that multiple-phase synergy effectively suppresses non-uniform deformation,thereby delaying the onset of vertical splitting cracks.An optimal combination of compressive strength-plasticity is achieved by the(NbMoTa)_(92.5)C_(7.5) alloy.The significant improvement in room-temperature mechanical properties can be attributed to its hierarchical microstructure:in the mesoscale,the BCC matrix is divided by eutectic structures;while at the microscale,the BCC matrix is further refined by abundant lath-like FCC precipitates.The FCC precip-itates contain high-density stacking faults,acting as a dislocation source under compressive loading.The HCP phase in the eutectic microstructures,in turn,acts as a strong barrier to dislocation movement and simultaneously increases the dislocation storage capacity.These findings open a new route to tailor the microstructure and mechanical properties of RH/MEAs.展开更多
Up-and-coming high-temperature materials,refractory high entropy alloys,are suffering from lower oxidation resistance,restricting their applications in the aerospace field.In this study,two novel treatments of Al-depo...Up-and-coming high-temperature materials,refractory high entropy alloys,are suffering from lower oxidation resistance,restricting their applications in the aerospace field.In this study,two novel treatments of Al-deposited and remelted were developed to refine the microstructure and enhance the oxidation resistance of refractory high entropy alloy using electron beam freeform fabrication(EBF3).Finer and short-range ordering structures were observed in the remelted sample,whereas the Al-deposited sample showcased the formation of silicide and intermetallic phases.High-temperature cyclic and isothermal oxidation tests at 1000℃ were carried out.The total weight gain after 60 h of cyclic oxidation decreased by 17.49%and 30.46%for the remelted and deposited samples,respectively,compared to the as-cast state.Oxidation kinetics reveal an evident lower mass gain and oxidation rate in the treated samples.A multilayer oxide consisting of TiO_(2)+Al_(2)O_(3)+SiO_(2)+AlNbO_(4) was studied for its excellent oxidation resistance.The oxidation behavior of rutile,corundum and other oxides was analyzed using first principles calculations and chemical defect analysis.Overall,this research,which introduces novel treatments,offers promising insights for enhancing the inherent oxidation resistance of refractory high entropy alloys.展开更多
Grain boundary engineering plays a significant role in the improvement of strength and plasticity of alloys. However, in refractory high-entropy alloys, the susceptibility of grain boundaries to oxygen presents a bott...Grain boundary engineering plays a significant role in the improvement of strength and plasticity of alloys. However, in refractory high-entropy alloys, the susceptibility of grain boundaries to oxygen presents a bottleneck in achieving high mechanical performance. Creating a large number of clean grain boundaries in refractory high-entropy alloys is a challenge. In this study, an ultrafine-grained (UFG) NbMoTaW alloy with high grain-boundary cohesion was prepared by powder metallurgy, taking advantages of rapid hot-pressing sintering and full-process inert atmosphere protection from powder synthesis to sintering. By oxygen control and an increase in the proportion of grain boundaries, the segregation of oxygen and formation of oxides at grain boundaries were strongly mitigated, thus the intrinsic high cohesion of the interfaces was preserved. Compared to the coarse-grained alloys prepared by arc-melting and those sintered by traditional powder metallurgy methods, the UFG NbMoTaW alloy demonstrated simultaneously increased strength and plasticity at ambient temperature. The highly cohesive grain boundaries not only reduce brittle fractures effectively but also promote intragranular deformation. Consequently, the UFG NbMoTaW alloy achieved a high yield strength even at elevated temperatures, with a remarkable performance of 1117 MPa at 1200 ℃. This work provides a feasible solution for producing refractory high-entropy alloys with low impurity content, refined microstructure, and excellent mechanical performance.展开更多
Hydrogen-based mineral phase transformation(HMPT)technology has demonstrated its effectiveness in separating iron and enriching rare earths from Bayan Obo refractory ores.However,further research is needed to clarify ...Hydrogen-based mineral phase transformation(HMPT)technology has demonstrated its effectiveness in separating iron and enriching rare earths from Bayan Obo refractory ores.However,further research is needed to clarify the phase composition and floatability of rare earths obtained after HMPT owing to the associated phase transformations.This study explored the mineralogical characteristics and separation behavior of rare earths in HMPT-treated iron tailings.Process mineralogy studies conducted via BGRIMM process mineralogy analysis and X-ray diffraction revealed that the main valuable minerals in the tailings included rare-earth oxides(9.15wt%),monazite(5.31wt%),and fluorite(23.52wt%).The study also examined the impact of mineral liberation and gangue mineral intergrowth on flotation performance.Flotation tests achieved a rare-earth oxide(REO)grade of 74.12wt% with a recovery of 34.17% in open-circuit flotation,whereas closed-circuit flotation resulted in a REO grade of 60.27wt% with a recovery of 73%.Transmission electron microscopy and scanning electron microscopy coupled with energy-dispersive spectroscopy revealed that monazite remained stable during the HMPT process,while bastnaesite was transformed into Ce_(7)O_(12)and CeF_(3),leading to increased collector consumption.Nonetheless,the HMPT process did not significantly affect the flotation performance of rare earths.The enrichment of fluorite in the tailings highlighted its further recovery potential.The integration of HMPT with magnetic separation and flotation presents an efficient strategy for recovering rare earths,iron,and fluorite from Bayan Obo ores.展开更多
BACKGROUND A case study of multiple distinct levels of skipped thoracolumbar spine infection was reported in which 13 successful vacuum sealing drainage(VSD)surgeries were treated.CASE SUMMARY The patient underwent a ...BACKGROUND A case study of multiple distinct levels of skipped thoracolumbar spine infection was reported in which 13 successful vacuum sealing drainage(VSD)surgeries were treated.CASE SUMMARY The patient underwent a total of 13 procedures within our medical facility,including five performed under local anesthesia and eight performed under general anesthesia.The source of the ailment was ultimately identified as Enterobacter cloacae.After the last procedure,the patient's symptoms were alleviated,and the recovery process was satisfactory.Three months post-operation,the Japanese Orthopaedic Association scores had improved to 100%.Imageological examination revealed a satisfactory position of internal fixation,and the abnormal signals in the vertebral body and intervertebral space had been eliminated when compared to the pre-operative results.CONCLUSION The study demonstrates that the extreme lateral approach debridement combined with multiple VSD operations is a secure and successful method of treatment for recurrent spinal infection,providing an alternative to traditional surgery.展开更多
Introducing B2 ordering can effectively improve the mechanical properties of lightweight refractory high-entropy alloys(LRHEAs).However,(Zr,Al)-enriched B2 precipitates generally reduce the ductility because their ord...Introducing B2 ordering can effectively improve the mechanical properties of lightweight refractory high-entropy alloys(LRHEAs).However,(Zr,Al)-enriched B2 precipitates generally reduce the ductility because their ordering characteristic is destroyed after dislocation shearing.Meanwhile,the local chemical order(LCO)cannot provide an adequate strengthening effect due to its small size.展开更多
1 Production and Running Status of China’s Refractories Industry in 20241.1 Production and Running Status In 2024,according to the statistical data from The Association of China Refractories Industry,China’s refract...1 Production and Running Status of China’s Refractories Industry in 20241.1 Production and Running Status In 2024,according to the statistical data from The Association of China Refractories Industry,China’s refractories output was 22.0711million tons,decreasing by 3.73%YOY;in which the outputs of dense shaped refractory products,insulating refractory products and monolithic refractories were 11.3163 million tons decreasing by 6.07%YOY,83.77 thousand tons increasing by 11.17%YOY,and 9.9971 million tons decreasing by 2.07%YOY,respectively.The outputs of the main varieties are shown in Fig.1.展开更多
Henan refractories industry is a major refractory production base in China,which is also an advantage industry in Henan province.Recently,Henan provincial government has formulated relevant industrial and environmenta...Henan refractories industry is a major refractory production base in China,which is also an advantage industry in Henan province.Recently,Henan provincial government has formulated relevant industrial and environmental protection policies,and approved the construction of“Henan Province New Refractory Industry Cluster”.Henan’s main refractory enterprises have developed a series of green technologies,processes and products,and carried out automation and intelligent transformation,equipment upgrading,and the deep integration of information technology and refractory manufacturing through interconnection and digital empowerment.To promote the high-quality development of refractory industry,The Association of Henan Refractory Industry has established a series of standards and evaluation systems of refractories including air pollutant emission,energy consumption limits,carbon emission limits,green products,etc.The Association of Henan Refractory Industry also organized exchanges and mutual cooperation between enterprises inside and outside the region,and guided the development of specialization,refinement and innovation.This paper summarized the relevant works of refractories in Henan,and put forward some suggestions for solving the existing problems of refractories in Henan.展开更多
Mgo-Cao refractories are widely used in the iron and steel metalurgy industry due to their advantages of purifying molten steel,high refractoriness,good thermal shock resistance,and excellent corrosion resistance to b...Mgo-Cao refractories are widely used in the iron and steel metalurgy industry due to their advantages of purifying molten steel,high refractoriness,good thermal shock resistance,and excellent corrosion resistance to basic slags.However,hydration occurs during the manufacturing,storage,and transportation of refractories,which severely limits their application.Mgo-CaO clinker is the main raw material for Mgo-Cao refractories,and its hydration resistance determines the development of the latter case.Herein,the Mgo-Cao clinker was modified using myristic acid as the modifying agent by the liquid-phase deposition method.The effects of the particle size of the raw materials,concentration of myristic acid,treatment temperature and time on the phase composition and hydration resistance of the modified Mgo-Cao clinkers were investigated in detail.The results show that the samples with an agent concentration of 0.25 mol L^(-1) and treated at 25℃ for 1 h exhibit the optimal hydration resistance properties,namely a low hydration mass gain rate(0.23%)and a large water contact angle(152.9).展开更多
Mullite has a high melting point,high hardness,good thermal shock resistance,corrosion resistance,and high-temperature mechanical properties.Mullite raw materials are mostly synthesized by the sintering method and ele...Mullite has a high melting point,high hardness,good thermal shock resistance,corrosion resistance,and high-temperature mechanical properties.Mullite raw materials are mostly synthesized by the sintering method and electric fused method.The research and application progress of pure mullite and its composite refractories in fields such as ceramics,metallurgy,aerospace,military industry,cement and glass were reviewed.The future development trend of mullite in the application of refractories was prospected.展开更多
Laboratory experiments and thermodynamic calculations were performed to investigate the interfacial reactions between the MgO-C refractory and the steel with and without the lanthanum(La)addition.Following a reaction ...Laboratory experiments and thermodynamic calculations were performed to investigate the interfacial reactions between the MgO-C refractory and the steel with and without the lanthanum(La)addition.Following a reaction time of 50 min,a reaction layer comprised MgO and CaS with a thickness of 30μm was observed at the interface between the La-free steel and refractory.The MgO layer was observed in La-bearing steel after just 10 min of reaction.The addition of La to the steel accelerated the formation of the MgO layer.As the reaction time increased,a La-containing layer was formed at the La-bearing steel/refractory interface.This La-containing layer progressed through stages from La_(2)O_(2)S+La2O3→La-Ca-O-S→La-Ca-O→La-Ca-Al-O.Furthermore,the evolution of oxide inclusions in the La-free steel followed the sequence of MgO⋅Al_(2)O_(3),Ti-Ca-Al-O and Ti-Mg-Al-O→MgO·Al_(2)O_(3)and MgO with increasing the reaction time.In contrast,the sequence for the La-bearing steel was:La_(2)O_(2)S and La2O3→La_(2)O_(2)S and La-Ti-Al-Mg-O→La-Ti-Al-Mg-O,MgO and MgO·Al_(2)O_(3).The average penetration depth of the La-bearing steel into the refractory was notably lower than that of the La-free steel,revealing that the incorporation of rare earth element La in steel exhibits a significant inhibitory effect on the penetration of molten steel into the MgO-C refractory.展开更多
Dear Editor,I diopathic macular telangiectasia(MacTel)type 1 is a retinal vascular disease characterized by abnormal dilation of macular capillaries,leading to metamorphopsia,progressive vision loss,and temporal scoto...Dear Editor,I diopathic macular telangiectasia(MacTel)type 1 is a retinal vascular disease characterized by abnormal dilation of macular capillaries,leading to metamorphopsia,progressive vision loss,and temporal scotoma enlargement.Currently,there is no standardized treatment protocol for MacTel type 1[1-2].Treatment outcomes can vary significantly among individuals,highlighting the ongoing need for further exploration of new and more effective treatment options.This paper presents a case of refractory macular edema associated with MacTel type 1,which showed a favorable response to pars plana vitrectomy(PPV)and internal limiting membrane(ILM)peeling.展开更多
Refractory high-entropy alloys(RHEAs)exhibit outstanding strength at room temperature,but their high-temperature applications are hindered by severe strain-softening.Here,we report slip-band-driven dy-namic recrystall...Refractory high-entropy alloys(RHEAs)exhibit outstanding strength at room temperature,but their high-temperature applications are hindered by severe strain-softening.Here,we report slip-band-driven dy-namic recrystallization to enhance the high-temperature strain hardening of HfNbTaTiZr RHEA.By intro-ducing partial lattice defects through hot forging,we increase the nucleation sites for dynamic recrys-tallization during subsequent thermomechanical deformation,thus suppressing the strain-softening be-havior.We reveal that the high-temperature deformation is governed by the formation of heterogeneous bimodal grains along slip bands,which effectively constrain dislocation motion and improve strength,while microbands prevent premature failure.The fracture mode also changes from ductile to mixed to cleavage-dominated with increasing temperature.Our results demonstrate a simple and effective method for overcoming high-temperature strain-softening for BCC high entropy alloys.展开更多
The TiNbV_(0.5)Ta_(0.5)Cr_(x)(x=0,0.1,0.2,0.5)refractory high-entropy alloys(RHEAs)with an excellent combination of ductility and strength were designed and prepared for high-temperature applications.The yield strengt...The TiNbV_(0.5)Ta_(0.5)Cr_(x)(x=0,0.1,0.2,0.5)refractory high-entropy alloys(RHEAs)with an excellent combination of ductility and strength were designed and prepared for high-temperature applications.The yield strength,ultimate tensile strength,and elongation of the TiNbV_(0.5)Ta_(0.5)Cr_(0.1) alloy were 878 MPa,928 MPa,and 21.6%,respectively.Important issues of microstructure evolution,precipitation process,and their impact on mechanical properties were concerned.Then,the effect of Cr content on the mechanical properties of TiNbV_(0.5)Ta_(0.5)Cr_(x) alloys was evaluated through a quantitative analysis of the strengthening mechanism,which elucidated the trade-offrelationship between solid solution strengthening and precipitation strengthening in RHEA.The microstructure evolution of the TiNbV_(0.5)Ta_(0.5)Cr_(x) alloys involved the formation and interconversion of titanium allotropes(α-Ti and β-Ti)and the precipitation of the Laves phase.Significant embrittlement was induced by the preferential precipitation of α-Ti on the grain boundary.The TiNbV_(0.5)Ta_(0.5)Cr_(x) alloys exhibited an incubation period for Laves phase precipitation,which was related to the Cr content in the alloy.The Laves phase preferentially nucleated next to α-Ti due to the redistribution of elements during the α-Ti precipitation process.The precipitation of the Laves phase played an important role in enhancing the strength of the TiNbV_(0.5)Ta_(0.5)Cr_(x) alloys.展开更多
Currently,chemical furnaces play an important role in the chemical industry.It is necessary to ensure their quality and operation performance,so as to guarantee the efficiency of chemical production.Compared with othe...Currently,chemical furnaces play an important role in the chemical industry.It is necessary to ensure their quality and operation performance,so as to guarantee the efficiency of chemical production.Compared with other furnaces,chemical furnaces have strong particularity,which puts forward higher requirements for the thermal shock resistance of the refractories of furnace linings.This paper studied the thermal shock resistance of the refractories for chemical furnace linings,and proposed measures for improvement,providing experience and technical support for the safe production of chemical enterprises.展开更多
Refractory wounds cause significant harm to the health of patients and the most common treatments in clinical practice are surgical debridement and wound dressings.However,certain challenges,including surgical difficu...Refractory wounds cause significant harm to the health of patients and the most common treatments in clinical practice are surgical debridement and wound dressings.However,certain challenges,including surgical difficulty,lengthy recovery times,and a high recurrence rate persist.Conductive hydrogel dressings with combined monitoring and therapeutic properties have strong advantages in promoting wound healing due to the stimulation of endogenous current on wounds and are the focus of recent advancements.Therefore,this review introduces the mechanism of conductive hydrogel used for wound monitoring and healing,the materials selection of conductive hydrogel dressings used for wound monitoring,focuses on the conductive hydrogel sensor to monitor the output categories of wound status signals,proving invaluable for non-invasive,real-time evaluation of wound condition to encourage wound healing.Notably,the research of artificial intelligence(AI)model based on sensor derived data to predict the wound healing state,AI makes use of this abundant data set to forecast and optimize the trajectory of tissue regeneration and assess the stage of wound healing.Finally,refractory wounds including pressure ulcers,diabetes ulcers and articular wounds,and the corresponding wound monitoring and healing process are discussed in detail.This manuscript supports the growth of clinically linked disciplines and offers motivation to researchers working in the multidisciplinary field of conductive hydrogel dressings.展开更多
Multiple myeloma is a complex and challenging blood cancer,particularly in cases where the disease has relapsed or become resistant to treatment.These situations often have a significant impact on both patient surviva...Multiple myeloma is a complex and challenging blood cancer,particularly in cases where the disease has relapsed or become resistant to treatment.These situations often have a significant impact on both patient survival and quality of life.Over recent years,advances in precision medicine and translational medicine have brought about a shift in treatment strategies,moving toward more personalized and targeted approaches.This review highlights the latest developments in the management of refractory and relapsed multiple myeloma,focusing on the current state of precision diagnosis and treatment,the role of translational medicine,and potential future directions in research.By reviewing key studies and clinical trial data,we aim to offer fresh perspectives and strategies that could improve clinical outcomes.展开更多
Refractory metals and their alloys have excellent properties such as high-temperature strength and corrosion resistance.It is widely used in aerospace,electronics industry and other fields.However,refractory alloys ar...Refractory metals and their alloys have excellent properties such as high-temperature strength and corrosion resistance.It is widely used in aerospace,electronics industry and other fields.However,refractory alloys are prone to oxidation and failure in high-temperature service environments.The preparation of a MoSi_(2) antioxidant coating is an effective method for improving the protective ability of refractory metals at high temperatures.However,although MoSi_(2) coatings have many advantages,it is difficult to meet the increasingly stringent service requirements.To address these challenges,researchers have used different elements to modify a single MoSi_(2) coating and improve its overall oxidation resistance.In this study,the roles of one or more elements(Si,B,N,Zr,Al,W,Hf,Y,Ti and Cr)in MoSi_(2) coatings are systematically reviewed.Simultaneously,the mechanism of single or multiple synergistic modification of MoSi_(2) coatings with different elements was discussed.Finally,the development prospects of MoSi_(2) coating modification of refractory metals and their alloys are discussed.展开更多
基金the Key Project of the National Natural Science Foundation of China(Grant Nos.U21A2058 and 51802235)the Hubei Science and Technology Innovation Talent Project(Grant No.2023DJC087).
文摘MgO-CaO(40 wt.%CaO)refractory aggregates were prepared using the calcined dolomite and light-burned magnesia fine powder as raw materials and TiO_(2) as additive.The effect of TiO_(2) on their phase composition,microstructures and properties was investigated by X-ray diffraction and scanning electron microscopy.The properties such as bulk density,apparent porosity,relative aggregate tube strength and hydration resistance were also investigated.The results showed that the CaTiO_(3) generated by the reaction between CaO and TiO_(2) was distributed around the CaO grain boundaries and intermittently distributed with MgO,which formed an isolation layer around CaO and greatly improved the hydration resistance.Meanwhile,the introduction of TiO_(2) promoted sintering and increased the grain size,further improving the strengths and hydration resistance of the materials.In addition,the most significant enhancement in the hydration resistance and strengths of the samples was achieved when 1.0-2.0 wt.%TiO_(2) was added.In this case,the relative strength of aggregate increased from 33.3% to 37.3%-43.1%,and the mass gain after the hydration test decreased from 3.13% to 1.26%-1.45%.
基金support from the National Natural Science Foundation of China(Grant Nos.U1860205 and 52204352)Youth Project of Hubei Natural Science Foundation(Grant No.2022CFB593)+1 种基金Key R&D Project of Hubei Province(Grant No.2022BAA021)Guiding Project of Scientific Research Plan of Hubei Provincial Department of Education(Grant No.B2022019).
文摘The interaction of MgO-MgAl_(2)O_(4)-based and MgO-Cr_(2)O_(3)-based refractories with X70 molten steel was studied by immersion experiments at 1560℃.The effects of immersion time(30 and 60 min)on the contents of total oxygen(TO),Al,Nb,Si,Mn,and Cr as well as the composition,number density,and size distribution of inclusions in the molten steel were investigated.The influence of the penetration and erosion degree of the molten steel to the refractory on the steel-refractory interface layer was analyzed.The results show that,at 1560℃,the MgO-MgAl_(2)O_(4)-based refractory can better control the contents of TO and the composition of molten steel compared with the MgO-Cr_(2)O_(3)-based refractory.The TO content is only 16×10^(-4) wt.%in the molten steel after reacted with the Mg0-MgAl_(2)O_(4)-based refractory at the end point of refining,4 accounting for 11.5%of that reacted with the MgO-Cr_(2)O_(3)-based refractory(139×10^(-4) wt.%).The number density of inclusions is only 14 mm^(-2),and the average size ofinclusions is only 1.31μm,with thelargest proportion of inclusions in 1-2μm(70%).The Al_(2)O_(3)-MnS-CaO complex inclusions in the original steel changed to complex inclusions dominated by Cr-Nb-Mn-S-O and MgO.Al_(2)O_(3),corresponding to the MgO-Cr_(2)O_(3)-based and MgO-MgAl_(2)O_(4)-based refractories,respectively.The MgO.Al_(2)O_(3) layer was formed at the reaction interface between MgO-MgAl_(2)O_(4)-based refractory and molten steel,which is helpful to restrict the erosion of refractories and the pollution of molten steel.The damage mechanism of the MgO-Cr_(2)O_(3)-based refractory is mainly permeation and chemical reaction,while the damage of the MgO-MgAl_(2)O_(4)-based refractory is mainlyscouring erosion.
基金financial support from the Na-tional Natural Science Foundation of China(No.52231006)National Key Research and Development Program of China(No.2017YFB0702003)the National Natural Science Foundation of China(No.51871217).
文摘Refractory high/medium-entropy alloys(RH/MEAs)are known for their outstanding performance at el-evated temperatures;however,they usually exhibit poor room-temperature plasticity,which can be at-tributed to the non-uniform deformation that occurs at room temperature.Once cracks nucleate,they will rapidly propagate into vertical splitting cracks.Here,we introduce multiple phases including FCC and HCP phases into the NbMoTa RMEA via appropriate addition of carbon.The results show that multiple-phase synergy effectively suppresses non-uniform deformation,thereby delaying the onset of vertical splitting cracks.An optimal combination of compressive strength-plasticity is achieved by the(NbMoTa)_(92.5)C_(7.5) alloy.The significant improvement in room-temperature mechanical properties can be attributed to its hierarchical microstructure:in the mesoscale,the BCC matrix is divided by eutectic structures;while at the microscale,the BCC matrix is further refined by abundant lath-like FCC precipitates.The FCC precip-itates contain high-density stacking faults,acting as a dislocation source under compressive loading.The HCP phase in the eutectic microstructures,in turn,acts as a strong barrier to dislocation movement and simultaneously increases the dislocation storage capacity.These findings open a new route to tailor the microstructure and mechanical properties of RH/MEAs.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFF0609000)National Natural Science Foundation of China(Grant Nos.52171034 and 52101037)Postdoctoral Fellowship Program of CPSFara(No.GZB20230944).
文摘Up-and-coming high-temperature materials,refractory high entropy alloys,are suffering from lower oxidation resistance,restricting their applications in the aerospace field.In this study,two novel treatments of Al-deposited and remelted were developed to refine the microstructure and enhance the oxidation resistance of refractory high entropy alloy using electron beam freeform fabrication(EBF3).Finer and short-range ordering structures were observed in the remelted sample,whereas the Al-deposited sample showcased the formation of silicide and intermetallic phases.High-temperature cyclic and isothermal oxidation tests at 1000℃ were carried out.The total weight gain after 60 h of cyclic oxidation decreased by 17.49%and 30.46%for the remelted and deposited samples,respectively,compared to the as-cast state.Oxidation kinetics reveal an evident lower mass gain and oxidation rate in the treated samples.A multilayer oxide consisting of TiO_(2)+Al_(2)O_(3)+SiO_(2)+AlNbO_(4) was studied for its excellent oxidation resistance.The oxidation behavior of rutile,corundum and other oxides was analyzed using first principles calculations and chemical defect analysis.Overall,this research,which introduces novel treatments,offers promising insights for enhancing the inherent oxidation resistance of refractory high entropy alloys.
基金supported by the National Natural Science Foundation of China(Nos.52371128,52304378,52101031 and 92163107).
文摘Grain boundary engineering plays a significant role in the improvement of strength and plasticity of alloys. However, in refractory high-entropy alloys, the susceptibility of grain boundaries to oxygen presents a bottleneck in achieving high mechanical performance. Creating a large number of clean grain boundaries in refractory high-entropy alloys is a challenge. In this study, an ultrafine-grained (UFG) NbMoTaW alloy with high grain-boundary cohesion was prepared by powder metallurgy, taking advantages of rapid hot-pressing sintering and full-process inert atmosphere protection from powder synthesis to sintering. By oxygen control and an increase in the proportion of grain boundaries, the segregation of oxygen and formation of oxides at grain boundaries were strongly mitigated, thus the intrinsic high cohesion of the interfaces was preserved. Compared to the coarse-grained alloys prepared by arc-melting and those sintered by traditional powder metallurgy methods, the UFG NbMoTaW alloy demonstrated simultaneously increased strength and plasticity at ambient temperature. The highly cohesive grain boundaries not only reduce brittle fractures effectively but also promote intragranular deformation. Consequently, the UFG NbMoTaW alloy achieved a high yield strength even at elevated temperatures, with a remarkable performance of 1117 MPa at 1200 ℃. This work provides a feasible solution for producing refractory high-entropy alloys with low impurity content, refined microstructure, and excellent mechanical performance.
基金the financial support received from the Key Program of National Natural Science Foundation of China(No.52130406)the National Key R&D Program of China(Nos.2021YFC2901000 and 2022YFC2905800)+1 种基金the General Program of National Natural Science Foundation of China(No.52274253)Natural Science Foundation Innovation Group Project of Hubei Province,China(No.2023AFA044)。
文摘Hydrogen-based mineral phase transformation(HMPT)technology has demonstrated its effectiveness in separating iron and enriching rare earths from Bayan Obo refractory ores.However,further research is needed to clarify the phase composition and floatability of rare earths obtained after HMPT owing to the associated phase transformations.This study explored the mineralogical characteristics and separation behavior of rare earths in HMPT-treated iron tailings.Process mineralogy studies conducted via BGRIMM process mineralogy analysis and X-ray diffraction revealed that the main valuable minerals in the tailings included rare-earth oxides(9.15wt%),monazite(5.31wt%),and fluorite(23.52wt%).The study also examined the impact of mineral liberation and gangue mineral intergrowth on flotation performance.Flotation tests achieved a rare-earth oxide(REO)grade of 74.12wt% with a recovery of 34.17% in open-circuit flotation,whereas closed-circuit flotation resulted in a REO grade of 60.27wt% with a recovery of 73%.Transmission electron microscopy and scanning electron microscopy coupled with energy-dispersive spectroscopy revealed that monazite remained stable during the HMPT process,while bastnaesite was transformed into Ce_(7)O_(12)and CeF_(3),leading to increased collector consumption.Nonetheless,the HMPT process did not significantly affect the flotation performance of rare earths.The enrichment of fluorite in the tailings highlighted its further recovery potential.The integration of HMPT with magnetic separation and flotation presents an efficient strategy for recovering rare earths,iron,and fluorite from Bayan Obo ores.
基金Supported by Natural Science Foundation of Shandong Province,No.ZR2023MH331.
文摘BACKGROUND A case study of multiple distinct levels of skipped thoracolumbar spine infection was reported in which 13 successful vacuum sealing drainage(VSD)surgeries were treated.CASE SUMMARY The patient underwent a total of 13 procedures within our medical facility,including five performed under local anesthesia and eight performed under general anesthesia.The source of the ailment was ultimately identified as Enterobacter cloacae.After the last procedure,the patient's symptoms were alleviated,and the recovery process was satisfactory.Three months post-operation,the Japanese Orthopaedic Association scores had improved to 100%.Imageological examination revealed a satisfactory position of internal fixation,and the abnormal signals in the vertebral body and intervertebral space had been eliminated when compared to the pre-operative results.CONCLUSION The study demonstrates that the extreme lateral approach debridement combined with multiple VSD operations is a secure and successful method of treatment for recurrent spinal infection,providing an alternative to traditional surgery.
基金supported by the National Natural Science Foundation of China(Nos.52171166 and U20A20231)the Natural Science Foundation of Hunan Province,China(Nos.2024JJ2060 and 2024JJ5406)+1 种基金the Key Laboratory of Materials in Dynamic Extremes of Sichuan Province(No.2023SCKT1102)the Postgraduate Scientific Research Innovation Project of National University of Defense Technology(No.XJJC2024065).
文摘Introducing B2 ordering can effectively improve the mechanical properties of lightweight refractory high-entropy alloys(LRHEAs).However,(Zr,Al)-enriched B2 precipitates generally reduce the ductility because their ordering characteristic is destroyed after dislocation shearing.Meanwhile,the local chemical order(LCO)cannot provide an adequate strengthening effect due to its small size.
文摘1 Production and Running Status of China’s Refractories Industry in 20241.1 Production and Running Status In 2024,according to the statistical data from The Association of China Refractories Industry,China’s refractories output was 22.0711million tons,decreasing by 3.73%YOY;in which the outputs of dense shaped refractory products,insulating refractory products and monolithic refractories were 11.3163 million tons decreasing by 6.07%YOY,83.77 thousand tons increasing by 11.17%YOY,and 9.9971 million tons decreasing by 2.07%YOY,respectively.The outputs of the main varieties are shown in Fig.1.
文摘Henan refractories industry is a major refractory production base in China,which is also an advantage industry in Henan province.Recently,Henan provincial government has formulated relevant industrial and environmental protection policies,and approved the construction of“Henan Province New Refractory Industry Cluster”.Henan’s main refractory enterprises have developed a series of green technologies,processes and products,and carried out automation and intelligent transformation,equipment upgrading,and the deep integration of information technology and refractory manufacturing through interconnection and digital empowerment.To promote the high-quality development of refractory industry,The Association of Henan Refractory Industry has established a series of standards and evaluation systems of refractories including air pollutant emission,energy consumption limits,carbon emission limits,green products,etc.The Association of Henan Refractory Industry also organized exchanges and mutual cooperation between enterprises inside and outside the region,and guided the development of specialization,refinement and innovation.This paper summarized the relevant works of refractories in Henan,and put forward some suggestions for solving the existing problems of refractories in Henan.
基金National Natural Science Foundation of China(Grants 52202025 and U23A20559)Natural Science Foundation of Hubei Province(Grant 2022CFB629)+1 种基金"The 14^(th)Five-Year Plan"Hubei Provincial Advantaged Characteristic Disciplines(Groups)Project of Wuhan University of Science and Technology(2023A0307).
文摘Mgo-Cao refractories are widely used in the iron and steel metalurgy industry due to their advantages of purifying molten steel,high refractoriness,good thermal shock resistance,and excellent corrosion resistance to basic slags.However,hydration occurs during the manufacturing,storage,and transportation of refractories,which severely limits their application.Mgo-CaO clinker is the main raw material for Mgo-Cao refractories,and its hydration resistance determines the development of the latter case.Herein,the Mgo-Cao clinker was modified using myristic acid as the modifying agent by the liquid-phase deposition method.The effects of the particle size of the raw materials,concentration of myristic acid,treatment temperature and time on the phase composition and hydration resistance of the modified Mgo-Cao clinkers were investigated in detail.The results show that the samples with an agent concentration of 0.25 mol L^(-1) and treated at 25℃ for 1 h exhibit the optimal hydration resistance properties,namely a low hydration mass gain rate(0.23%)and a large water contact angle(152.9).
基金supported by the Starting Grants of Institute of Metal Research,Chinese Academy of Science(E255L401).
文摘Mullite has a high melting point,high hardness,good thermal shock resistance,corrosion resistance,and high-temperature mechanical properties.Mullite raw materials are mostly synthesized by the sintering method and electric fused method.The research and application progress of pure mullite and its composite refractories in fields such as ceramics,metallurgy,aerospace,military industry,cement and glass were reviewed.The future development trend of mullite in the application of refractories was prospected.
基金the support from the National Key R&D Program(No.2023YFB3709900)the National Key R&D Program(No.2023YFB3709901)+2 种基金the National Natural Science Foundation of China(Grant No.U22A20171)the Hebei Natural Science Foundation(Grant No.52304340)the High Steel Center(HSC)at North China University of Technology.
文摘Laboratory experiments and thermodynamic calculations were performed to investigate the interfacial reactions between the MgO-C refractory and the steel with and without the lanthanum(La)addition.Following a reaction time of 50 min,a reaction layer comprised MgO and CaS with a thickness of 30μm was observed at the interface between the La-free steel and refractory.The MgO layer was observed in La-bearing steel after just 10 min of reaction.The addition of La to the steel accelerated the formation of the MgO layer.As the reaction time increased,a La-containing layer was formed at the La-bearing steel/refractory interface.This La-containing layer progressed through stages from La_(2)O_(2)S+La2O3→La-Ca-O-S→La-Ca-O→La-Ca-Al-O.Furthermore,the evolution of oxide inclusions in the La-free steel followed the sequence of MgO⋅Al_(2)O_(3),Ti-Ca-Al-O and Ti-Mg-Al-O→MgO·Al_(2)O_(3)and MgO with increasing the reaction time.In contrast,the sequence for the La-bearing steel was:La_(2)O_(2)S and La2O3→La_(2)O_(2)S and La-Ti-Al-Mg-O→La-Ti-Al-Mg-O,MgO and MgO·Al_(2)O_(3).The average penetration depth of the La-bearing steel into the refractory was notably lower than that of the La-free steel,revealing that the incorporation of rare earth element La in steel exhibits a significant inhibitory effect on the penetration of molten steel into the MgO-C refractory.
基金Supported by Science and Technology Project of Sichuan Provincial Health Commission(No.24WXXT13)North Sichuan Medical College Doctor Start-up Fund Project(No.CBY24-QDA01).
文摘Dear Editor,I diopathic macular telangiectasia(MacTel)type 1 is a retinal vascular disease characterized by abnormal dilation of macular capillaries,leading to metamorphopsia,progressive vision loss,and temporal scotoma enlargement.Currently,there is no standardized treatment protocol for MacTel type 1[1-2].Treatment outcomes can vary significantly among individuals,highlighting the ongoing need for further exploration of new and more effective treatment options.This paper presents a case of refractory macular edema associated with MacTel type 1,which showed a favorable response to pars plana vitrectomy(PPV)and internal limiting membrane(ILM)peeling.
基金supported by the Aviation Foundation(No.2023Z0530S6004)Program 173(No.2020-JCIQ-ZD-186-01)+4 种基金the Space Utilization System of China Manned Space Engineering(No.KJZ-YY-NCL08)the Shanghai“Super Postdoc”Incentive Program(No.2023314)the National High-end Foreign Experts Introduction Program(No.G2023014006)the Zhenjiang International Science and Technology Cooperation Program(No.GJ2023011)the Jiangsu University(High-tech ship)Collaborative Innovation Center Program(No.XTCX202401).
文摘Refractory high-entropy alloys(RHEAs)exhibit outstanding strength at room temperature,but their high-temperature applications are hindered by severe strain-softening.Here,we report slip-band-driven dy-namic recrystallization to enhance the high-temperature strain hardening of HfNbTaTiZr RHEA.By intro-ducing partial lattice defects through hot forging,we increase the nucleation sites for dynamic recrys-tallization during subsequent thermomechanical deformation,thus suppressing the strain-softening be-havior.We reveal that the high-temperature deformation is governed by the formation of heterogeneous bimodal grains along slip bands,which effectively constrain dislocation motion and improve strength,while microbands prevent premature failure.The fracture mode also changes from ductile to mixed to cleavage-dominated with increasing temperature.Our results demonstrate a simple and effective method for overcoming high-temperature strain-softening for BCC high entropy alloys.
基金supported by the National Natural Science Foundation of China(Nos.51971021,52203382,and 11775017)the National Magnetic Confinement Fusion Program of China(No.2019YFE03130002)the Young Talent Fund of Association for Science and Technology in Shaanxi,China(No.20230415).
文摘The TiNbV_(0.5)Ta_(0.5)Cr_(x)(x=0,0.1,0.2,0.5)refractory high-entropy alloys(RHEAs)with an excellent combination of ductility and strength were designed and prepared for high-temperature applications.The yield strength,ultimate tensile strength,and elongation of the TiNbV_(0.5)Ta_(0.5)Cr_(0.1) alloy were 878 MPa,928 MPa,and 21.6%,respectively.Important issues of microstructure evolution,precipitation process,and their impact on mechanical properties were concerned.Then,the effect of Cr content on the mechanical properties of TiNbV_(0.5)Ta_(0.5)Cr_(x) alloys was evaluated through a quantitative analysis of the strengthening mechanism,which elucidated the trade-offrelationship between solid solution strengthening and precipitation strengthening in RHEA.The microstructure evolution of the TiNbV_(0.5)Ta_(0.5)Cr_(x) alloys involved the formation and interconversion of titanium allotropes(α-Ti and β-Ti)and the precipitation of the Laves phase.Significant embrittlement was induced by the preferential precipitation of α-Ti on the grain boundary.The TiNbV_(0.5)Ta_(0.5)Cr_(x) alloys exhibited an incubation period for Laves phase precipitation,which was related to the Cr content in the alloy.The Laves phase preferentially nucleated next to α-Ti due to the redistribution of elements during the α-Ti precipitation process.The precipitation of the Laves phase played an important role in enhancing the strength of the TiNbV_(0.5)Ta_(0.5)Cr_(x) alloys.
文摘Currently,chemical furnaces play an important role in the chemical industry.It is necessary to ensure their quality and operation performance,so as to guarantee the efficiency of chemical production.Compared with other furnaces,chemical furnaces have strong particularity,which puts forward higher requirements for the thermal shock resistance of the refractories of furnace linings.This paper studied the thermal shock resistance of the refractories for chemical furnace linings,and proposed measures for improvement,providing experience and technical support for the safe production of chemical enterprises.
基金supports received from Scientific Research Fund of Liaoning Province Education Department(Grant No.JYTQN 2023025)Scientific Research Fund of Liaoning Province Education Department(Grant No.JYTQN 2023025)+3 种基金the Natural Science Foundation of Liaoning Province(Grant No.2024-MS-075)the National Natural Science Foundation of China(32201179)National Key R&D Program of China(2023YFC2508200)Liaoning Provincial Natural Science Foundation Joint Fund(General Support Program Project)(2023-MSBA-093).
文摘Refractory wounds cause significant harm to the health of patients and the most common treatments in clinical practice are surgical debridement and wound dressings.However,certain challenges,including surgical difficulty,lengthy recovery times,and a high recurrence rate persist.Conductive hydrogel dressings with combined monitoring and therapeutic properties have strong advantages in promoting wound healing due to the stimulation of endogenous current on wounds and are the focus of recent advancements.Therefore,this review introduces the mechanism of conductive hydrogel used for wound monitoring and healing,the materials selection of conductive hydrogel dressings used for wound monitoring,focuses on the conductive hydrogel sensor to monitor the output categories of wound status signals,proving invaluable for non-invasive,real-time evaluation of wound condition to encourage wound healing.Notably,the research of artificial intelligence(AI)model based on sensor derived data to predict the wound healing state,AI makes use of this abundant data set to forecast and optimize the trajectory of tissue regeneration and assess the stage of wound healing.Finally,refractory wounds including pressure ulcers,diabetes ulcers and articular wounds,and the corresponding wound monitoring and healing process are discussed in detail.This manuscript supports the growth of clinically linked disciplines and offers motivation to researchers working in the multidisciplinary field of conductive hydrogel dressings.
基金supported by grants from the 925th Science Foundation(Grant Nos.2023-3 and 2024-2/3).
文摘Multiple myeloma is a complex and challenging blood cancer,particularly in cases where the disease has relapsed or become resistant to treatment.These situations often have a significant impact on both patient survival and quality of life.Over recent years,advances in precision medicine and translational medicine have brought about a shift in treatment strategies,moving toward more personalized and targeted approaches.This review highlights the latest developments in the management of refractory and relapsed multiple myeloma,focusing on the current state of precision diagnosis and treatment,the role of translational medicine,and potential future directions in research.By reviewing key studies and clinical trial data,we aim to offer fresh perspectives and strategies that could improve clinical outcomes.
基金supported by the National Natural Science Foundation of China(No.52374401 and 52404409)the Key R&D Plan of Shaanxi Province(Nos.2024QCYKXJ-116 and 2023JBGS-14)+3 种基金the Scientific and Technological Innovation Team Project of Shaanxi Innovation Capability Support Plan(No.2022TD-30)Xi’an Science and Technology Plan Project(No.2023JHGXRC-0020)the“Young Talent Support Project”of China Association for Science and Technology of China.The Natural Science Foundation of Shaanxi Provincial(No.2024JC-YBQN-0367)China Postdoctoral Science Foundation(2024MD753961).
文摘Refractory metals and their alloys have excellent properties such as high-temperature strength and corrosion resistance.It is widely used in aerospace,electronics industry and other fields.However,refractory alloys are prone to oxidation and failure in high-temperature service environments.The preparation of a MoSi_(2) antioxidant coating is an effective method for improving the protective ability of refractory metals at high temperatures.However,although MoSi_(2) coatings have many advantages,it is difficult to meet the increasingly stringent service requirements.To address these challenges,researchers have used different elements to modify a single MoSi_(2) coating and improve its overall oxidation resistance.In this study,the roles of one or more elements(Si,B,N,Zr,Al,W,Hf,Y,Ti and Cr)in MoSi_(2) coatings are systematically reviewed.Simultaneously,the mechanism of single or multiple synergistic modification of MoSi_(2) coatings with different elements was discussed.Finally,the development prospects of MoSi_(2) coating modification of refractory metals and their alloys are discussed.
