FCC,BCC and B2 phases,the most common phases in high-entropy alloys(HEAs),are widely investigated to tailor their mechanical and magnetic performances.The detailed investigation of FCC to BCC/B2 phase transformation o...FCC,BCC and B2 phases,the most common phases in high-entropy alloys(HEAs),are widely investigated to tailor their mechanical and magnetic performances.The detailed investigation of FCC to BCC/B2 phase transformation of Al Co Cr Fe Ni HEA in this paper reveals its evolution and structure-properties relations in terms of both temperature and holding duration.With increasing heat treatment temperature and duration,such transition will progress simultaneously at both the dendric core(DC)region and interdendric(ID)region and the volume of phase transformation from FCC to BCC phases is greater than FCC to B2 phases,resulting in increased yield strength and saturation magnetization.The obvious phase transition of the Al Co Cr Fe Ni HEA at 1200℃can enhance its yield strength and saturation magnetization as a sacrifice of its fracture strain.However,an excellent combination of mechanical-magnetic properties was achieved when heat-treated at 1100℃for 50 h by optimizing both the transformation and the size of B2 phases.Our present study could pave ways to design the HEAs or other alloys with an optimum combination of mechanical and magnetic properties for application-oriented viewpoints.展开更多
Phase constitutions,either changed by alloying or by phase transformation,are the key factors to determine the magnetic and mechanical performances of high-entropy alloys(HEAs).Using the AlCoCrFeNi HEA as a candidate ...Phase constitutions,either changed by alloying or by phase transformation,are the key factors to determine the magnetic and mechanical performances of high-entropy alloys(HEAs).Using the AlCoCrFeNi HEA as a candidate alloy,this paper demonstrates the effect of phase transformation on both the mechanical and magnetic properties in the multi-phase system.With increasing heat treatment temperature,the sigma(σ)and face-centered-cubic(FCC)phases disappeared at 1000℃and 1200℃,respectively.Such volume fraction changes ofσ,FCC and body-centered-cubic(BCC)phases have divergent effects on mechanical and magnetic properties.The excellent strength-ductility combination will be achieved as the disappearance ofσphase and formation of FCC phase.As for the magnetic properties,the volume fraction of BCC phase plays a major role in determining its saturation magnetization.When the volume fraction change of BCC phase is not evident,the higher volume fraction of FCC phase will influence its magnetization at 2 T.Our present work might provide insights into analyzing the evolution of both mechanical and magnetic properties of HEAs caused by complex phase transformation.展开更多
基金supported by the Natural Science Foundation of China(51774240 and 51690163)the fund of the State Key Laboratory of Solidification Processing in NWPU(2019-TS-04)+3 种基金Innovation Capability Support Program of Shaanxi(2020KJXX-073)the Natural Science Foundation of Chongqing(cstc2020jcyj-msxmX0976)the National Training Program of Innovation and Entrepreneurship for Undergraduates(Grant NO.S202010699160)the Fundamental Research Funds for the Central Universities。
文摘FCC,BCC and B2 phases,the most common phases in high-entropy alloys(HEAs),are widely investigated to tailor their mechanical and magnetic performances.The detailed investigation of FCC to BCC/B2 phase transformation of Al Co Cr Fe Ni HEA in this paper reveals its evolution and structure-properties relations in terms of both temperature and holding duration.With increasing heat treatment temperature and duration,such transition will progress simultaneously at both the dendric core(DC)region and interdendric(ID)region and the volume of phase transformation from FCC to BCC phases is greater than FCC to B2 phases,resulting in increased yield strength and saturation magnetization.The obvious phase transition of the Al Co Cr Fe Ni HEA at 1200℃can enhance its yield strength and saturation magnetization as a sacrifice of its fracture strain.However,an excellent combination of mechanical-magnetic properties was achieved when heat-treated at 1100℃for 50 h by optimizing both the transformation and the size of B2 phases.Our present study could pave ways to design the HEAs or other alloys with an optimum combination of mechanical and magnetic properties for application-oriented viewpoints.
基金supported by the Natural Science Foundation of China(51774240 and 51690163)the fund of the State Key Laboratory of Solidification Processing in NWPU(2019-TS-04)+1 种基金Innovation Capability Support Program of Shaanxi(2020KJXX-073)the Fundamental Research Funds for the Central Universities。
文摘Phase constitutions,either changed by alloying or by phase transformation,are the key factors to determine the magnetic and mechanical performances of high-entropy alloys(HEAs).Using the AlCoCrFeNi HEA as a candidate alloy,this paper demonstrates the effect of phase transformation on both the mechanical and magnetic properties in the multi-phase system.With increasing heat treatment temperature,the sigma(σ)and face-centered-cubic(FCC)phases disappeared at 1000℃and 1200℃,respectively.Such volume fraction changes ofσ,FCC and body-centered-cubic(BCC)phases have divergent effects on mechanical and magnetic properties.The excellent strength-ductility combination will be achieved as the disappearance ofσphase and formation of FCC phase.As for the magnetic properties,the volume fraction of BCC phase plays a major role in determining its saturation magnetization.When the volume fraction change of BCC phase is not evident,the higher volume fraction of FCC phase will influence its magnetization at 2 T.Our present work might provide insights into analyzing the evolution of both mechanical and magnetic properties of HEAs caused by complex phase transformation.
