轧制变形对CrCoNi中熵合金组织及性能的影响

通过真空悬浮熔炼炉熔炼制备了CrCoNi中熵合金,采用900 ℃热轧(变形量50%)、500 ℃温轧(变形量50%)获得轧制板材,利用光学显微镜、X射线衍射仪、扫描电镜、硬度计和万能试验机,研究轧制变形对合金组织结构和力学性能的影响。结果表明:CrCoNi中熵合金铸态时为简单的单相FCC固溶体结构,随着轧制变形的进行,无新相产生;CrCoNi合金有较好的塑性变形能力,塑性变形后其力学性能得到大幅度的提升,热轧后,其抗拉强度能达到890 MPa,伸长率能达到60%,并且通过加大变形量以及热轧+温轧的组合可实现强度的进一步的提升;严重的晶格畸变、加工硬化以及细晶强化共同促进了其高强度与良好韧性的结合。

Effect of rolling deformation on microstructure and properties of CrCoNi medium-entropy alloy

A CrCoNi medium-entropy alloy was prepared by using vacuum suspension melting furnace, then hot rolled at 900 ℃ for 50% deformation and further warm rolled at 500 ℃ for 50% deformation. The effect of rolling deformation on microstructure and mechanical properties of the CrCoNi alloy was studied by means of OM, XRD, SEM, hardness tester and universal test machine. The results show that the CrCoNi medium-entropy alloy has a simple single-phase FCC solid solution structure in as-cast state, and no new phase is generated during rolling deformation. The CrCoNi alloy has good plastic deformation ability, and its performance is greatly improved after plastic deformation. The tensile strength can reach 890 MPa and the elongation can reach 60% after hot rolling, and the strength can be further increased by increasing deformation and the combination of hot rolling+warm rolling. Severe lattice distortion, work hardening and fine-grain strengthening all promote the combination of high strength and good toughness.