固溶处理对准共晶Al-Si合金显微组织及力学性能的影响

石 磊，王有祁，王 英，苏 辉，甄立玲

(中国兵器科学研究院 宁波分院，宁波 315103)

摘 要：通过金相显微镜、差示扫描量热分析以及显微硬度测试等研究固溶温度和固溶时间对挤压铸造的ZAlSi12CuMgNi铝合金的显微组织和力学性能变化的影响。结果发现：在固溶过程中，强化相逐渐溶解，共晶Si逐渐细化、弥散，块状初晶Si趋于圆整化；保温时间过长，细化后的Si会发生聚集、粗化、长大，块状Si圆整度下降以及α(Al)晶粒长大等现象；随着固溶温度的上升，强化相的溶解和Si相的粒化、圆整化的时间会缩短，且Si相的细化程度和弥散程度更高，而Si相粗化和α(Al)晶粒长大的速度也会增大；在不同固溶温度下，α(Al)固溶体的力学性能随保温时间的延长而呈现不同形式的下降趋势；挤压铸造的ZAlSi12CuMgNi铝合金的最佳固溶处理工艺为525~530 ℃，保温时间为2.5~3 h。

关键词：挤压铸造；固溶处理；ZAlSi12CuMgNi铝合金；显微组织；力学性能

Effect of solution treatment on microstructure and mechanical properties of quasi eutectic Al-Si alloy

SHI Lei, WANG You-qi, WANG Ying, SU Hui, ZHEN Li-ling

(Ningbo Branch, Ordnance Science Institute of China, Ningbo 315103, China)

Abstract:The effects of solution temperature and time on the evolution of microstructures and mechanical properties of squeezing casting ZAlSi12CuMgNi aluminium alloy were analyzed by metallography microscopy, differential scanning calorimetry(DSC) and microhardness tests. The results show that the intermetallic phases dissolve and the Si phases are fine, spheroidized and disperse gradually. The fine Si phases congregate, coarsen and grow when the solution time is too long. The coarsening velocity of Si phases will rise, and the time of intermetallic phases dissolved and Si phases spheroidized will be shorter with the increase of solution temperature, in addition, the degrees of dispersal and spheroidization of Si phases become greater. The mechanical properties of α(Al) solid solution show different formats with the solution prolonging at different solution temperatures. The best solution treatment is solution-treated at 525-530 ℃ for 2.5-3 h.

Key words:squeezing casting; solution treatment; ZAlSi12CuMgNi aluminium alloy; microstructure; mechanical property