Hot-air forming of Al-Mg-Cr alloy and prediction of failure based on Zener-Holloman parameter

초록

The microstructure of an Al-Mg-Cr alloy tube fabricated through indirect extrusion at 673 K showed elongated grains with a mean size of similar to 26 mu m. The strain rate-stress relationship at high temperatures (753 K to 793 K) revealed that dislocation climb creep was the rate-controlling deformation mechanism. The hot-air forming process was successful at a pressure of 70 bar. The Zener-Hollomon parameter based failure criterion was 3602+, and was used to explain the failure behavior of a deforming body. The forming and fracture behavior of the Al-Mg-Cr alloy tube was analyzed with the aid of finite element (FE) simulation, into which the failure criterion was incorporated. Comparison of the simulation and the experimental results indicated that the proposed fracture criterion was useful in predicting the fracture behavior of aluminum tube deforming by means of gas pressure.

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