高压热处理对Cu-37.67Zn-1.43Al合金导热及导电性能的影响

Thermal Conductivity and Electrical Conductivity of Cu-37.67Zn-1.43Al Alloy with High Pressure Heat Treatment

采用热常数测试仪和电导仪测试了Cu-37.67Zn-1.43Al合金经1~5 GPa,700℃保温20 min处理前后的热导率和电导率,用光学显微镜和透射电镜对其组织特征进行观察,并探讨了高压热处理对Cu-37.67Zn-1.43Al合金导热性能和导电性能的影响。结果表明：退火态Cu-37.67Zn-1.43Al合金的原始组织由α相和少量的β相组成。经高压热处理后,合金组织中白色块状α相数量减少,出现细条状α相,组织明显细化,细化效果随压力的增大先增强后减弱,当压力为3 GPa时,组织细化效果最好。并且,高压热处理能降低Cu-37.67Zn-1.43Al合金的热导率和电导率,在1~5 GPa范围内,随着压力的增大,该合金的热导率和电导率均先降低后升高;压力为3 GPa时,热导率和电导率均达到最低值,分别为99 W·m-1·K-1和20.86%IACS,较高压处理前分别降低了14.66%和15.07%,但经高压处理与未经高压处理的样品热导率差值随着温度的升高而逐渐减小,在25℃时,两者的差值为17 W·m-1·K-1,而在400℃时,两者的差值为4 W·m-1·K-1。其原因主要是高压热处理后Cu-37.67Zn-1.43Al合金组织细化及组织内位错密度增大。

The thermal conductivity and electrical conductivity of Cu-37.67Zn-1.43A1 alloy before and after heat treatment at 1 - 5 GPa and 700 ℃ for 20 rain were measured by thermal constant tester and electric conductivity instrument, the microstructure was ob- served by means of optical microscope （OM） , transmission electronic microscope （ TEM ） , and the effect of high pressure heat treat- ment on thermal conductivity and electrical conductivity of Cu-37.67Zn-1.43A1 alloy were investigated. The results showed that the o- riginal microstructure of annealed Cu-37.67Zn-1.43A1 alloy was composed of c~ phase and a small amount of β phase. After high pres-sure heat treatment, the number of white massive a phases reduced, thin strips a phase appeared, the microstructure was obviously re- fined, and the refinement effect increased with the pressure increasing firstly and then decreased. When the pressure was 3 GPa, the refinement effect was the best. The high pressure heat treatment could reduce the thermal conductivity and electrical conductivity of the alloy, and the thermal conductivity and electrical conductivity firstly decreased and then increased as the pressure increased under 1 ~ 5 GPa pressure. The thermal conductivity and electrical conductivity reached the minimum values of 99 W·m-1.K-l and 20.86% IACS under 3 GPa, respectively, decreasing by 14.66% and 15.07%, respectively, compared with those of the alloy without high pressure treatment, but the margin values of their thermal conductivity decreased gradually as the temperature increased, which were 17 W＇m-I.K-1 at 25 ~C and 4 W.m-I.K-1 at 400 ~C, respectively. The main reason was that the microstructure was refined and the dislocation density within the grains of the alloy increased due to high pressure heat treatment.