Effects of Ti addition on the microstructures and mechanical properties of AICrFeNiMo0.5 Tix （x = 0, 0.25, 0.4, 0.5, 0.6, 0.75） high entropy alloys （HEAs） are investigated. All these HEAs of various Ti contents po...Effects of Ti addition on the microstructures and mechanical properties of AICrFeNiMo0.5 Tix （x = 0, 0.25, 0.4, 0.5, 0.6, 0.75） high entropy alloys （HEAs） are investigated. All these HEAs of various Ti contents possess dual BCC structures, indicating that Ti addition does not induce the formation of any new phase in these alloys. As Ti addition x varies from 0 to 0.75, the Vickers hardness （HV） of the alloy system increases from 623.7HV to 766.2HV, whereas the compressive yield stress firstly increases and then decreases with increasing x above 0.5. Meanwhile, the compressive ductility of the alloy system decreases with Ti addition. The AlCrFeNiMo0.5 Ti0.6 and AlCrFeNiMo0.5Ti0.75 HEAs become brittle and fracture with very limited plasticity. In the AlCrFeNiMo0.5Tix HEAs, the AlCrFeNiMoo.5 HEA possesses the highest compressive fracture strength of 4027 MPa and the largest compressive plastic strain of 27.9%, while the AlCrFeNiMo0.5 Ti0.5 HEA has the highest compressive yield strength of 2229 MPa and a compressive plastic strain of 10.1%. The combination of high strength and large plasticity of the AICrFeNiMoo.sTix （x = 0, 0.25, 0.4, 0.5） HEAs demonstrates that this alloy system is very promising for engineering applications.展开更多
采用1.0、1.2、1.4和1.6的轧制异速比对高温退火Cr Co Ni中熵合金进行室温和深冷异步轧制,并对轧后的材料在873、973和1073 K退火处理0.5 h。采用透射电子显微镜对轧制态样品进行微观表征,发现轧制态合金晶粒尺寸随着异速比增加而减小,...采用1.0、1.2、1.4和1.6的轧制异速比对高温退火Cr Co Ni中熵合金进行室温和深冷异步轧制,并对轧后的材料在873、973和1073 K退火处理0.5 h。采用透射电子显微镜对轧制态样品进行微观表征,发现轧制态合金晶粒尺寸随着异速比增加而减小,且存在明显的孪晶。室温异步轧制实验显示,轧制后轧制态和退火态合金的抗拉强度均随着轧制异速比的增加而增加。深冷轧制制备的材料具有比室温轧制更高的强度,但深冷轧制过程异速比对材料强度影响不明显。在深冷异步轧制过程中,由于内应力和轧制缺陷的累积使得异速比强化有一定的饱和度。采用场发射扫描电子显微镜对拉伸试样的断口形貌进行表征,发现室温异步轧制后合金具有明显的韧窝,而深冷异步轧制韧窝相对较浅,为剪切断裂。展开更多
On purpose of studying the sluggish diffusion of high-entropy alloys, three different face centered cubic Co-Cr-Cu-Fe-Ni high-entropy alloys were prepared, and assembled into three groups of sandwich- type diffusion m...On purpose of studying the sluggish diffusion of high-entropy alloys, three different face centered cubic Co-Cr-Cu-Fe-Ni high-entropy alloys were prepared, and assembled into three groups of sandwich- type diffusion multiple annealed at 1273, 1323, and 1373 K respectively. By means of the electron probe microanalyzer technique and recently developed numerical inverse method, the composition- dependent interdiffusivities at different temperatures were effectively evaluated by minimizing the residual between the model-predicted compositions/interdiffusion fluxes and the respectively experi- mental ones. After that, the tracer diffusivities were predicted based on the assessed mobility parameters and thermodynamic descriptions with the simplified ideal solution model. The comprehensive compari- son between the interdiffusivities/tracer diffusivities in the Co-Cr-Cu-Fe-Ni high-entropy alloys and those in sub-binary, ternary, quaternary and other quinary alloys indicates that the sluggish diffusion exists in interdiffusion instead of tracer diffusion for the present Co-Cr-Cu-Fe-Ni high-entropy alloys.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 51571127
文摘Effects of Ti addition on the microstructures and mechanical properties of AICrFeNiMo0.5 Tix （x = 0, 0.25, 0.4, 0.5, 0.6, 0.75） high entropy alloys （HEAs） are investigated. All these HEAs of various Ti contents possess dual BCC structures, indicating that Ti addition does not induce the formation of any new phase in these alloys. As Ti addition x varies from 0 to 0.75, the Vickers hardness （HV） of the alloy system increases from 623.7HV to 766.2HV, whereas the compressive yield stress firstly increases and then decreases with increasing x above 0.5. Meanwhile, the compressive ductility of the alloy system decreases with Ti addition. The AlCrFeNiMo0.5 Ti0.6 and AlCrFeNiMo0.5Ti0.75 HEAs become brittle and fracture with very limited plasticity. In the AlCrFeNiMo0.5Tix HEAs, the AlCrFeNiMoo.5 HEA possesses the highest compressive fracture strength of 4027 MPa and the largest compressive plastic strain of 27.9%, while the AlCrFeNiMo0.5 Ti0.5 HEA has the highest compressive yield strength of 2229 MPa and a compressive plastic strain of 10.1%. The combination of high strength and large plasticity of the AICrFeNiMoo.sTix （x = 0, 0.25, 0.4, 0.5） HEAs demonstrates that this alloy system is very promising for engineering applications.
文摘采用1.0、1.2、1.4和1.6的轧制异速比对高温退火Cr Co Ni中熵合金进行室温和深冷异步轧制,并对轧后的材料在873、973和1073 K退火处理0.5 h。采用透射电子显微镜对轧制态样品进行微观表征,发现轧制态合金晶粒尺寸随着异速比增加而减小,且存在明显的孪晶。室温异步轧制实验显示,轧制后轧制态和退火态合金的抗拉强度均随着轧制异速比的增加而增加。深冷轧制制备的材料具有比室温轧制更高的强度,但深冷轧制过程异速比对材料强度影响不明显。在深冷异步轧制过程中,由于内应力和轧制缺陷的累积使得异速比强化有一定的饱和度。采用场发射扫描电子显微镜对拉伸试样的断口形貌进行表征,发现室温异步轧制后合金具有明显的韧窝,而深冷异步轧制韧窝相对较浅,为剪切断裂。
基金The authors are grateful for the financial supports from the National Natural Science Foundation of China(51771035,51671037)Natural Science Foundation of Jiangsu Province,China(BK20161190)the Priority Academic Program of Jiangsu Higher Education Institutions,China.
基金financially supported by the National Natural Science Foundation of China(Grant No.51474239)the National Key Research and Development Program of China(Grant No.2016YFB0301101)+1 种基金financial support from the Huxiang Youth Talent Plan released by Hunan Province,Chinathe project supported by State Key Laboratory of Powder Metallurgy Foundation,Central South University,Changsha,China
文摘On purpose of studying the sluggish diffusion of high-entropy alloys, three different face centered cubic Co-Cr-Cu-Fe-Ni high-entropy alloys were prepared, and assembled into three groups of sandwich- type diffusion multiple annealed at 1273, 1323, and 1373 K respectively. By means of the electron probe microanalyzer technique and recently developed numerical inverse method, the composition- dependent interdiffusivities at different temperatures were effectively evaluated by minimizing the residual between the model-predicted compositions/interdiffusion fluxes and the respectively experi- mental ones. After that, the tracer diffusivities were predicted based on the assessed mobility parameters and thermodynamic descriptions with the simplified ideal solution model. The comprehensive compari- son between the interdiffusivities/tracer diffusivities in the Co-Cr-Cu-Fe-Ni high-entropy alloys and those in sub-binary, ternary, quaternary and other quinary alloys indicates that the sluggish diffusion exists in interdiffusion instead of tracer diffusion for the present Co-Cr-Cu-Fe-Ni high-entropy alloys.
