铝含量和退火温度对锆铝合金相组成和力学性能的影响

Effect of Al Content and Annealing Temperature on Phase Compositions and Mechanical Properties of ZrAl Alloys

利用非自耗电弧炉熔炼了Al含量为6.0%,7.0%,8.0%(质量分数)的锆铝二元合金,通过退火过程中的包析反应得到了不同相组成的Zr3Al基合金,借助光学显微镜、XRD分析研究了合金的金相组织和相组成,进行了显微硬度测定和拉伸试验。结果表明:铸态的锆铝合金显微硬度随着铝含量的增加而增大;退火可得到组织均匀的Zr3Al基合金,其显微硬度和抗拉强度主要与相组成和基体晶粒大小有关,而与第二相的形态无关;合金的显微硬度、抗拉强度随着Zr3Al相的增多而增大,延伸率随着Zr3Al相的增多而减小;合金的显微硬度、抗拉强度和延伸率随着Zr3Al晶粒的细化而不同程度地增大。

ZrAl alloys with three different Al contents （6.0, 7.0, 8.0, wt%） were melted by the non-consumable electric-arc furnace. Zr3Al-based alloys with different phase compositions were obtained by peritectoid reaction during the annealing process. Microstructures and phase compositions of alloys was studied by optical microscope and XRD, and then its microhardnesses and tensile properties were tested. The results show that the microhardness of as-cast ZrAl alloys increases with the increase of Al content. Homogeneous microstructure of Zr3Al-based alloys can be obtained by annealing. Its microhardness and tensile strength are relative to matrix grain size and phase composition, but independent of the form and distribution of the second phases. Microhardness and tensile strength of the annealed alloy increase with the increase of Zr3Al content, while the elongation decreases. In addition, microhardness, tensile strength and elongation of the annealed alloys increase with Zr3Al grain refinement. Key words： Zr3Al-based alloys; annealing; phase composition; mechanical properties