搅拌摩擦加工优化Al-Si-Mg-Sc合金的力学性能

Mechanical Properties of Al-Si-Mg-Sc Alloys by Friction Stir Processing Optimization

分别对亚共晶与共晶Al-Si-Mg-Sc合金进行搅拌摩擦加工(FSP)及后续固溶时效(T6)热处理,研究了不同状态下Al-Si-Mg-Sc合金的微观结构及力学性能。结果表明,FSP可消除铸态合金的孔洞缺陷并破坏Si相网状结构,同时FSP还可碎化AlSiSc及AlMg(SiSc)Fe等金属间化合物相。后续T6处理可促使FSP态合金内析出高密度β″相。FSP可大幅优化T6态亚共晶与共晶Al-Si-Mg-Sc合金的力学性能,FSP+T6态合金的强化机制包括析出强化及细小过剩相强化,其断裂模式为典型的韧性断裂。

Friction stir processing(FSP)and subsequent solution and artificial aging(T6)treatment were conducted on hypoeutectic and eutectic Al-Si-Mg-Sc alloys,and the microstructure as well as mechanical properties of the alloy were investigated at different states.The results indicate that FSP can eliminate the hole defects and effectively destroy Si phase network structure,breaking intermetallic AlSiSc,AlMg(SiSc)Fe phases in the casting alloy.T6 treatment can promote the precipitation of high densityβ″phase in the FSP alloys.FSP can greatly optimize the mechanical properties of hypoeutectic and eutectic Al-Si-Mg-Sc alloys in T6 state.The strengthening mechanisms of the alloys with FSP and T6 treatment include precipitation strengthening and excess phase strengthening effects,and fracture mode is typical plastic fracture.