多层喷射沉积过共晶Al-Si-Cu-Mg合金的微观组织及力学性能

摘要

Hypereuteetic Al-Si alloys are widely applied in aerospace, automobfie and electricity industries because ofits good wear-resistance and low coefficient of thermal expansion. The value of hypereutectic Al-Si alloys is their fine pri-mary silicon particles. A hypereutectic Al-Si-Cu-Mg alloy is fabricated by multi-layer spray deposition technology whichhas more advantages than the traditional spray deposition such as higher cooling rate, simple technological route and loweroxidation. The microstructures of alloy as-deposited, as-extruded and after heat ueatment are observed. The result showsthat the primary silicon phase is fmc and uniformly distributed in the matrix. The tensile properties and fracture behaviorare also tested and analyzed. The strengthening and fracture mechanism are put forward at last.%多层喷射沉积技术具有冷速快、工艺简单、氧化程度低、制备的材料组织细小且分布均匀等特点．而使高硅铝合金充分发挥实用价值的关键是细化初晶硅．作者用多层喷射沉积技术制备了过共晶Al-Si-Cu-Mg合金，并与传统的铸态冶金制备的相同化学成分的合金进行了比较．对合金的沉积坯、热挤压处理后的微观组织进行了观察与分析．结果表明，多层喷射沉积合金的初晶硅大小只有25μm左右．并对合金的拉伸性能、扫描断口进行了测试与观察，提出了合金的强化与断裂机制．