Modulation of the Organization and Properties of Al-Cu Alloys by Alloying Elements

本文通过在Al-4.6Cu合金的基础上逐级添加过渡金属元素Ag、稀土元素Sc、陶瓷相形成元素Zr和C的方式，从而来研究耐热铝合金的多种元素对组织结构的调控机制，明确了其力学性能的强化效果可叠加。同时逐级添加元素之后的合金晶粒尺寸逐渐减少，析出相类型从单一的Al2Cu增加至Al2Cu、Al3Sc和ZrC三类析出相复合的组织结构；通过组织结构的均匀化程度作为判据，获得了最佳的固溶处理工艺，通过时效后组织的硬度，获得了最佳的时效处理工艺；结合力学性能测试，发现逐级增加微量元素的方式会造成铸态及热处理态后力学性能的提升，且高温测试表明250℃和300℃下的力学性能同样获得了改善。In this paper, by adding the transition metal element Ag, the rare earth element Sc, and the ceramic phase forming elements Zr and C step by step on the basis of Al-4.6Cu alloy, so as to study the mechanism of regulating the organization and structure of heat-resistant aluminum alloys by a variety of elements, and to make clear that the reinforcing effect of its mechanical properties can be superimposed. Meanwhile, the grain size of the alloy after adding elements step by step was gradually reduced, and the type of precipitation phase increased from single Al2Cu to the organizational structure of the composite of three types of precipitation phases, namely, Al2Cu, Al3Sc and ZrC; the optimal solid solution treatment process was obtained by using the degree of homogenization of the organizational structure as a criterion and the optimal aging treatment process was obtained by using the hardness of the organization after aging; In conjunction with mechanical property tests, it was found that the stepwise increase of trace elements resulted in improved mechanical properties in the as-cast and heat-treated states, and high-temperature tests showed that the same improvement in mechanical properties was obtained at 250˚C and 300˚C.