Fabrication and Microstructure Control of High-temperature-resistant Light Alloys Containing Fine Intermetallic Compounds

采用直流铸造和快速凝固技术制备了含过渡元素和稀土元素的铝合金。还制备了含银、金、铜、锌的铝锂合金。对含Y、Nd、Sm的镁合金进行了精心制备。观察了合金的析出组织、形变组织和再结晶组织，并评价了合金的高温力学性能。在含Sc的合金中，在623K左右形成了细小的L13型结构的Al3Sc析出物，这些析出物比Al3Zr更能有效地抑制再结晶。快速凝固的Al-Er和Al-Yb合金产生了非常细小的化合物，有望有效地改善合金的性能。在Al-Li合金中添加Ag、Au、Mg等元素，可提高合金中β‘相的相稳定性。添加Ag、Au和Mg也大大抑制了三角洲颗粒的粗化速度。含稀土元素的镁合金由于亚稳相的析出而显著提高了时效硬化速度。高温机械强度高于常规镁合金。这是因为含Y、ND和Sm的镁合金中的交叉滑移变形受到了抑制。结论：含过渡元素和稀土元素的Al和Mg合金在高温下具有良好的组织控制和良好的力学性能。

Aluminum alloys containing transition elements and rare earth elements such as Zr, Sc, Y,Er and Yb were produced using DC-cast and rapid solidification techniques. Al-Li alloys containing Ag, Au, Cu and Zn were also produced. Magnesium alloys containing Y,Nd and Sm were carefully fabricated. Precipitation microstructurs, deformed and recrystallized microstructures were observed and mechanical properties at high temperatures were evaluated.In the alloys containing Sc fine Al_3Sc precipitates with the L1_3-type structure were formed at temperatures around 623K.These precipitates were found to be more effective to retardrecrystallization than Al_3Zr ones. Rapidly solidified Al-Er and Al-Yb alloys produced extremely fine compounds which are expected to be effective to improve alloy properties. The phase stability of the delta'phase in Al-Li alloys was increased with the additional elements of Ag, Au and Mg. The coarsening rate of the delta'particles was also greatly suppressed by the additions of Ag, Au and Mg.Mgalloys containing rare earth elements exhibited markedly increased age-hardening due to the precipitation of the metastable phases. The mechanical strength at high temperatures was higher than that of the conventional Mg alloys. This is explained by the suppressed cross-slip deformation in the Mg alloys containing Y,Nd and Sm.To conclude Al and Mg alloys containing transition elements and rare earth elements produce well controlled microstructures and exhibit improved mechanical properties at high temperatures.