论文部分内容阅读
以冷却速率101～103K/s的不同凝固条件制备了Cu-10Ag合金及其原位纤维复合材料。研究了铸态和形变态合金的结构与性能。铸态合金的结构由Cu相、Ag沉淀相和(Cu+Ag)共晶组成。通过大变形发展为Cu-Ag合金原位纳米纤维复合材料,其中由Ag沉淀相所形成的Ag纤维尺寸(d)与真实应变(η)呈指数函数关系:d=C·exp(-0.228η),(Cu+Ag)共晶中Ag层转变为更细的纳米Ag纤维。Cu-Ag合金原位纳米纤维复合材料显示了两阶段应变强化效应:在低真实应变阶段主要表现为加工硬化或位错强化,在高真实应变阶段主要表现为超细Ag纤维强化或界面强化。快速凝固的Cu-Ag合金原位纳米纤维复合材料比慢速凝固材料具有更高的包括极限拉伸强度和电导率在内的综合性能。在形变过程中复合材料的强度与电导率的演变出于相同的结构原因。
Cu-10Ag alloy and its in-situ fiber composites were prepared at different cooling rates of 101 ~ 103K / s. The structure and properties of as-cast and deformed alloys were investigated. The structure of as-cast alloy is composed of Cu phase, Ag precipitated phase and (Cu + Ag) eutectic. The Cu-Ag alloy in-situ nanofibers composites were developed by large deformation, in which the Ag fiber size (d) formed by Ag precipitates exponentially with the true strain (η): d = C · exp (-0.228 η ), Ag (Cu + Ag) eutectic Ag layer into thinner nano-Ag fibers. The Cu-Ag alloy in-situ nanofiber composites show two-stage strain hardening effect: work hardening or dislocation strengthening mainly in the low true strain stage and mainly superfine Ag fiber strengthening or interface strengthening in the high real strain stage. The rapid solidification Cu-Ag alloy in-situ nanofibers composites have higher comprehensive properties, including ultimate tensile strength and electrical conductivity, than those of slow-setting materials. The evolution of the strength and conductivity of the composite during deformation is due to the same structural causes.