快速凝固Cu-5Ag-0.5Zr-0.4Cr-0.35Nb合金的组织与力学性能

采用快速凝固方法制备了Cu-5Ag-0.5Zr及Cu-5Ag-0.5Zr-0.4Cr-0.35Nb(wt%)合金粉末,采用热等静压将粉末压制成坯料,随后进行热锻、冷轧处理。测试了合金在室温及高温(500 ℃)下的力学性能,并分析了合金的显微组织及断口形貌。结果表明,冷轧态合金具有更优异的室温拉伸性能,冷轧态Cu-Ag-Zr合金抗拉强度为739.3 MPa,伸长率7.1%,这与铜基体中密集的Cu₄AgZr颗粒及纳米级Ag颗粒有关。除Cu₄AgZr颗粒及Ag颗粒外,Cr、Nb元素的添加还生成高温稳定的Cr₂Nb颗粒,同时提高了合金的室温和500 ℃拉伸强度。冷轧态Cu-Ag-Zr-Cr-Nb合金的室温极限抗拉强度和伸长率分别为799.1 MPa与5.3%。因为热锻态合金晶粒尺寸粗大,Ag颗粒尺寸细小,相比冷轧态合金拥有更好的抗高温弱化性能。热锻态Cu-Ag-Zr-Cr-Nb和Cu-Ag-Zr合金的500 ℃抗拉强度分别为186.8和129.2 MPa,而冷轧态Cu-Ag-Zr-Cr-Nb和Cu-Ag-Zr合金在500 ℃抗拉强度分别仅为113.1和95.4 MPa。

Microstructure and mechanical properties of rapidly solidified Cu-5Ag-0.5Zr-0.4Cr-0.35Nb alloy

Rapidly solidified Cu-5Ag-0.5Zr and Cu-5Ag-0.5Zr-0.4Cr-0.35Nb (wt%) powders were compacted by hot sostatic pressing (HIP) and followed by hot forging and cold rolling.The mechanical properties of the alloy at room temperature and high temperature (500 ℃) were tested, and the microstructure and fracture morphology of the alloy were analyzed. The results show that cold rolled alloy has better room temperature tensile properties, and the ultimate tensile strength and elongation at room temperature of cold rolled Cu-Ag-Zr alloy are 739.3 MPa and 7.1%, respectively, which is related to the dense Cu₄AgZr and nano-sized Ag particles in Cu matrix. Apart from Cu₄AgZr and Ag particles, the addition of Cr and Nb elements generates high temperature stable Cr₂Nb particles, which enhances the tensile strength of the alloy at both room temperature and 500 ℃. The ultimate tensile strength and elongation at room temperature of cold rolled Cu-Ag-Zr-Cr-Nb alloy are 799.1 MPa and 5.3%, respectively. The hot forged alloy has a better weakening resistance at high temperature than that of cold rolled alloy due to larger grain size and finer Ag particles.The hot forged Cu-Ag-Zr-Cr-Nb and Cu-Ag-Zr alloys have a tensile strength of 186.8 MPa and 129.2 MPa at 500 ℃, respectively, while the tensile strength of cold rolled Cu-Ag-Zr-Cr-Nb and Cu-Ag-Zr alloys at 500 ℃ is only 113.1 MPa and 95.4 MPa, respectively.