材料期刊网

利用X射线结构分析、金相分析、显微硬度及电阻测定等方法建立了Al-Mg-Ce三元系富Al角400和300℃等温截面相图。并测定了含Ce的Al-Mg合金常温力学性能和应力腐蚀性能。研究证明,Ce显著提高Al-Mg合金抗应力腐蚀性能是与组织变化有关。不含Ce时,β相沿晶界呈链球状分布。Ce的加入,破坏了β相的连续性,且数量大大减少,晶界净化,并在晶界形成含Ce的无沉淀带。

The 300 and 400℃ isothermal sections of the Al-rich corner of Al-Mg-Ce ternary phase diagram with composition of 0—36 wt-% Mg and 0—50 wt-% Ce have been studied by X-ray structural analysis, metallography, microhardness test and electrical resistance measurement. The regions of 4 single-phase, 8 double-phase and 4 triple-phase were detected in the given alloy composition. Two new ternary compounds T_1-and T_2-phase were found in the solid solution regions of 21—22 wt-% Mg-14.5—16 wt-% Ce and 27.5—28.5 wt-% Mg-40.5—41.5 wt-% Ce respectively. The mechanical properties at room temperature and the stress corrosion of Al-Mg alloy containing Ce have been also examined. Experimental data showed that the great improvement over SCC of the Al-Mg alloys is related to the change of their microstructure. The β-phase without Ce distributes as continuous chain structure along the grain boundary. While an addition of Ce to β-phase would destroy the continuity, eliminate the chain structure, purify the grain boundaryand form Ce-containing solution strip precipitates along the grain boundary.