JIANG Kai-xuan, ZHOU Yan-jun, SONG Ke-xing, YANG Ran, YU Yan, LIU Ya-hui, ZHANG Yan-min, CHEN Ji-dong, HUANG Kuan, LIU Dong-dong, YU Bo
First, the extruded Cu-15Ni-8Sn alloy was solution treated at different temperatures for 1 h, and the optimum solution temperature was optimized. On this basis, the alloy was aged at 400 ℃ for 2 h. Microstructure, fracture morphology, tensile strength and hardness of the extruded, solution treated and aged alloy were analyzed by means of optical microscope, scanning electron microscopy, tensile test and Rockwell hardness tester. The results show that a large number of Sn rich phases are distributed at the grain boundaries and in grains of the extruded alloy, the hardness of the alloy is 81.5 HRB, and the tensile strength is 597 MPa. With the increase of solution temperature, the grain size of the alloy begins to grow, and the second phase particles gradually dissolve into the matrix. When the solution temperature is 840 ℃, the second phase particles are almost completely dissolved into the matrix, and the grain size of the alloy is 75-180 μm; when the solution temperature reaches 860 ℃, the grains appear overburning, indicating that the optimum solution temperature of the alloy is 840 ℃, at this time, the hardness of the alloy is 55.6 HRB, and the tensile strength is 396.5 MPa. After aging, the mechanical properties of the alloy are significantly improved: the hardness is 105.4 HRB, and the tensile strength is 839.8 MPa, which are 89.6% and 112% higher than those of the alloy solution treated at 840 ℃.