Effect of Alloy Additions on Superplasticity in Thermomechanically Processed High Magnesium Aluminum-Magnesium Alloys

摘要

This research extends previous thesis work by Becker and Mills, and is concurrent with that of Stengel on the superplastic behavior of warm rolled high-Mg, Al-Mg alloys. In this work, the effect of various alloy additions were investigated. The following Al-Mg alloy compositions were studied: 8% Mg; 8% Mg-0.4% Cu; 8% Mg-0.4% Cu-0.5% Mn; 10% Mg; 10% Mg-0.4% Cu; 10% Mg-0.2% Mn. These materials were solution treated and hot worked at 440 C and then warm rolled at 300 C to 94% reduction. Tensile testing was then conducted for the as-rolled condition. The alloys were tested at temperatures ranging from room temperature to 300 C and at strain rates from .000056/sec to .14/sec. The copper addition has, on the same weight percentage basis, the same effect on superplasticity as does the addition of manganese to the alloy. The addition of small amounts (i.e., approximately 0.2 weight percent) of manganese appears to offer little advantage over the binary compositions in terms of super plasticity.