热处理对Cu-3.0Ni-0.75Si-0.3Co合金组织性能的影响

Effect of Heat Treatment on Microstructure and Properties of Cu-3.0Ni-0.75Si-0.3Co Alloy

研究了热处理对Cu-3.0Ni-0.75Si-0.3Co合金电导率、硬度和组织演变规律的影响,并探讨了合金的强化机理。结果表明,随固溶温度升高,合金的晶界和晶内的Ni3Si2和CoSi相粒子数量逐渐减少,合金的过饱和固溶度不断增大。在950℃×1h固溶后,由于第二相粒子的尺寸较小、数量很少,在扫描电镜图片中出现的第二相粒子未能在XRD图谱中发现,说明在950℃×1h固溶处理后溶质元素能较为充分溶于基体中。经950℃×1h固溶处理和60%的冷变形后,电导率随时效时间的延长而升高,之后趋于平稳。随着时效温度的升高,电导率也不断提高;硬度随时效时间的延长先升高,后降低;时效温度越高,到达峰值所需的时间越短。在950℃×1h固溶处理,经60%的冷变形,450℃×6h时效处理后,合金的综合性能较好,此时,合金硬度(HB)为257,电导率为20.18 MS/m。

Effects of heat treatment on the electrical conductivity hardness and microstructure evolution of Cu-3.0Ni-0.75Si-0.3Co alloy were investigated, and the strengthening mechanism of the alloy was de- scribed. The results show that the amounts of Ni3Si2 and CoSi phase particle in the grain and grain boundary of Cu-3.0Ni-0.75Si-0.3Co alloy are decreased and the super-saturation solid solubility is in- creased with the increase of the solution temperature by SEM （scanning electron microscopy） observa- tion. As a result of minor second phase particle with smaller sizes in the microstructure, the second phase particles cannot be observed on the SEM pictures by XRD after 950℃）〈 1 h solid solution treat- ment, which reveal that solute elements are sufficiently dissolved into copper matrix. The aging treat- ment is conducted at different temperatures after 950℃）〈 1 h solid solution treatment and cold rolling of 60% deformation ratios. The results show that the electrical conductivity is increased rapidly at firstly and then tends to be flattened with the increase of the aging time. The electrical conductivity is increased continuously with the increase of the aging temperature. And the hardness is increased at firstly and then decreased with the increase of the aging time. And with the increase of ageing temperature, time reaching hardness peak is shortened. The desirable comprehensive properties can be obtained at 950℃ × 1 h solid solution treatment, 60% cold rolling and 450 ℃× 6 h aging treatment, where hardness and e- lectrical conductivity reach 257HB and 20.18 MS/m, respectively.