AlCrCuFeNb_(x)NiTi高熵合金组织与性能研究

Microstructure and Properties of AlCrCuFeNb_(x)NiTi High Entropy Alloys

采用电弧熔炼制备了AlCrCuFeNb_(x)NiTi(x=0,0.25,0.5,1.0)高熵合金,研究不同Nb含量对AlCrCuFeNb_(x)NiTi高熵合金显微组织和力学性能的影响。结果表明:AlCrCuFeNb_(x)NiTi(x=0,0.25,0.5,1.0)高熵合金物相主要包含有序fcc的L2_(1)相和Laves相,还有少量的bcc(A2)和fcc相;Nb元素的添加能促进Laves相的生成且对Cu元素的偏析具有一定的抑制效果;通过相判据参数计算找到了适合AlCrCuFeNb_(x)NiTi高熵合金的相形成判据;添加适量的Nb元素能够改善AlCrCuFeNiTi六元高熵合金的力学性能;AlCrCuFeNb_(0.5)NiTi高熵合金具有较好的综合力学性能,抗压强度达到1587.4 MPa,硬度(HV)达到5688 MPa;Nb元素含量过高时会形成过多的Laves相使合金表现出过早脆化现象。

AlCrCuFeNb_(x)NiTi(x=0,0.25,0.5,1.0)high-entropy alloys were prepared by arc melting,and the effect of different Nb contents on the microstructures and mechanical properties of AlCrCuFeNb_(x)NiTi high-entropy alloys was studied.The results show that the phase of AlCrCuFeNb_(x)NiTi(x=0,0.25,0.5,1.0)high-entropy alloys consists of ordered fcc L2_(1) phase and Laves phase,together with minor bcc(A2)and fcc phases.The addition of Nb element can promote the formation of Laves phase and has a certain inhibitory effect on the segregation of Cu elements.The phase formation criterion suitable for AlCrCuFeNb_(x)NiTi high-entropy alloys is found through the calculation of phase criterion parameters.The addition of an appropriate amount of Nb can improve the mechanical properties of AlCrCuFeNiTi six-element high-entropy alloy.AlCrCuFeNb_(0.5)NiTi high-entropy alloy has better comprehensive mechanical properties.The compressive strength reaches 1587.4 MPa,and the hardness(HV)reaches 5688 MPa.When the Nb element content is too high,too much Laves phase will be formed and the alloy will exhibit premature embrittlement.