As important light-weight structure material, aluminum alloy has been widely used in automotive and aerospace industries, in which the manufacturing of parts with high strength and good dimensional accuracy has been the main task. In this paper, special device was developed to investigate the hot forming–quenching integrated process of cold-rolled 6A02 aluminum alloy sheet. Strengthening effect was reflected by Vickers hardness measuring and uniaxial tensile test. Microstructure examination was conducted to clarify the strengthening mechanism by scanning electron microscope (SEM), transmission electron microscopy(TEM) and electron backscattering diffraction (EBSD). Results show that Vickers hardness increases with solution time (

Experimental investigation on hot forming–quenching integrated process of 6A02 aluminum alloy sheet

Gas forming of ultra-high strength steel hollow part using air filled into sealed tube and resistance heating

This paper studies the effects of strain rate on dynamic mechanical behavior and microstructure evolution of 5A02-O aluminum alloy at room temperature. Based on the results of the dynamic tensile tests and compressive tests at strain rates of 1000–5000 s −1 by split Hopkinson bar as well as the results of quasi-static tests at strain rate of 0.001 s −1 , it is shown that with increasing strain rate, the flow stress and tensile strength significantly increase and notable strain hardening and thermal softening behaviors are observed for 5A02-O with elongation of 63.00% and softening ratio of 73.23% at the strain rate of 4000 s −1 . The strain rate sensitivity for 5A02-O is enhanced in the range of 1000–3000 s −1 . Scanning electron microscopy (SEM) observations illustrate that the fracture surfaces are characterized by larger and deeper dimple-like structure with more precipitates at higher strain rates, which indicates the ductile failure mode. The enhancement of ductility is interpreted via the inertia effect which may contribute to diffuse necking, slow down the necking development and delay the onset of fracture. Furthermore, transmission electron microscopy (TEM) observations show that higher strain rate leads to higher dislocation density, smaller cell size with thinner cell wall and the appearance of dislocation wall with parallel dislocation lines. Dislocation cells are incomplete under dynamic deformation. In addition, the micro-hardness of 5A02-O increases with increasing strain rate.

Effects of strain rate on dynamic mechanical behavior and microstructure evolution of 5A02-O aluminum alloy

http://www.ysxbcn.com/down/upfile/soft/20120106/23-p364.pdf

Jun Qi

Papers

An experimental investigation into the formability of hydroforming 5A02 Al-tubes at elevated temperature