(昆明貴金屬研究所，昆明 650221)
摘 要: 制備Cu-10Ag和Cu-10Ag-Ce合金原位纖維復合材料，研究結構變化與應變強化的關系。隨著真應變增大，復合材料中的Ag纖維平均尺寸呈真應變的負指數函數減小，而極限強度呈真應變的指數函數增大。按其結構變化，原位復合材料顯示兩種強化機制：低應變階段主要為加工硬化機制，高應變階段主要為超細Ag纖維及界面強化機制。增大凝固速率和添加微量Ce明顯細化合金的初始Ag相和Ag纖維尺寸，增高原位纖維復合材料的應變強化速率。在真應變?yōu)?/SPAN>10.4時，緩慢、快速凝固Cu-10Ag合金和Cu-10Ag-Ce合金原位纖維復合材料的Ag纖維平均直徑分別為140、90和80 nm，極限拉伸強度分別為1 250、1 370和1 430 MPa。
關鍵字: Cu-Ag合金；復合材料；強化效應；Ce添加劑
filamentary composites
（Kunming Institute of Precious Metals, Kunming 650221, China）
Abstract: Cu-10Ag and Cu-10Ag-Ce alloys in situ filamentary composites were prepared. The relationships of the ultimate tensile strengths (UTS) and microstructure evolution of the filamentary composites were studied. With increasing true strain, the sizes of Ag filaments in the composites decrease according to a negative exponential function of the true strain. The UTS of the composites increase also according to a exponential function of the true strain. The two-stage strengthening mechanisms were discussed on the evolution of microstructure during deformation process: at low true strain stage, the strengthening mechanism is mainly one caused by the working hardening controlled by dislocation increasing; at high true strain stage, the strengthening mechanism is mainly one caused by the super-fine Ag filaments and large coherent interfaces between Ag filaments and Cu matrix. The rapid solidification and trace Ce addition in the alloys obviously refine the sizes of original Ag precipitate in cast alloys and Ag filaments in the in situ composites, and therefore obviously increase the strain strengthening rate of the Cu-10Ag alloy in situ filamentary composites. As the true strain is 10.4, the average size of Ag filaments are about 140, 90 and 80 nm, and the ultimate tensile strengths are 1 250, 1 370 and 1 430 MPa in the Cu-10Ag alloys solidified slowly or rapidly, as well as in Cu-10Ag-0.05Ce alloy, respectively.
Key words: Cu-Ag alloy; composite; strengthening effect; Ce addition
