A STRUCTURAL MATERIAL PART OF A HIGH-SI MG-CONTAINING AL ALLOY AND THE MANUFACTURE METHOD THEREOF

摘要

A structural material part of a high-Si Mg-containing Al alloy, which includes sectional material, bar, sheet and forged part, is characterized in that the structural material part is manufactured by: casting an ingot by semi-casting process, pre-heat-treating to disperse eutectic Si phase particles, thermal-plastic working and heat-treating to obtain eventual shape and microstructure. The structural part comprises 0.2-2.0wt% Mg and 8-18wt% Si, and has homogeneous and fine microstructure which comprises Al matrix of equiaxial crystals with an average grain size of < 6µm and dispersing Si particles and other second-phase particles with anaverage grain size of < 5µm. A structural material part of high-Si Mg-containing wrought Al alloy with good plasticity and high strength can be manufactured by the method at a low cost without adding any modifier during casting.