The temperature dependence of superplastic characteristics and microstructures of PM Al-16Si-5Fealloy

Temperature dependence of the superplasticity and microstructure of an Al-1 6 wt.% Si-5 wt.% Fe-0.9 wt.% Cu-0.4 wt.% Mg-0.9 wt.% Zr alloy fabricated by powder metallurgy processing was examined at elevated temperatures. Superp lastic large elongations of > 300% were obtained at a temperature range, in which high strain-rate sensitivities (m value) were observed. and elongati on rapidly decreased with increasing temperature beyond superplastic flow r egion. While evidence of grain sliding and rotation was observed in the sup erplastic flow region, a brittle-like fracture was observed in high tempera ture region beyond superplastic flow region. It has also been realized in s ignificant grain growth during deformation leading to the decline of superp lasticity in the present alloy. (C) 2001 Elsevier Science B.V. All rights r eserved.