热处理和熔炼方式改变对AlCoCrFeNiTi0.2高熵合金的影响

Effect of heat treatment and melting method changing on AlCoCrFeNiTi0.2 high entropy alloy

摘要:

采用电弧熔炼方法设计制备了AlCoCrFeNiTi_0.2合金,发现铸态时的合金形成了B2相和BCC相,且室温压缩性能良好,压缩塑性为32.6%,屈服强度为1530.4 MPa,抗压强度为4035.0 MPa,硬度接近600 HV。在550℃、800℃和1050℃对其进行热处理,采用水冷的方式以保存高温相,三个温度对应的相组成分别为BCC+B2、BCC+B2+FCC+σ和BCC+B2+FCC,热处理后合金脆性和硬度升高。采用磁悬浮熔炼制备了大块AlCoCrFeNiTi_0.2合金,该合金成分分布比较均匀,形成了BCC+B2+σ三相,在600℃时压缩塑性为35.0%,且仍能保持1486.7 MPa的屈服强度,耐高温性能较好。

Abstract:

The AlCoCrFeNiTi_0.2 alloy was designed and prepared by the arc melting method. It was found that the as-cast alloy formed the B2 phase and the BCC phase, and showed good room temperature compressibility, compressive plasticity of 32.6%, yield strength of 1530.4 MPa, and compressive strength of 4035.0 MPa. The hardness is about 600 HV. It was heat-treated at 550°C, 800°C and 1050°C, and the high-temperature phase was preserved by water cooling. The phase composition corresponding to the three temperatures was BCC + B2, BCC + B2 + FCC + σ, and BCC + B2 + FCC. The brittleness and hardness of the alloy increase after heat treatment. A bulk AlCoCrFeNiTi_0.2 alloy was prepared by magnetic levitation melting. The alloy has a relatively uniform composition distribution, forming a BCC + B2 + σ three-phase structure. The compressive plasticity is 35.0% at 600°C, and it can still maintain a yield strength of 1486.7 MPa which is good at high temperature.