High Temperature Long-term Strength and Structure Design in High Strength Magnesium Alloys

通过实验研究了镁合金中的蠕变行为及其特征，并用最小蠕变速率法对其蠕变特征进行了比较。所研究的合金是镁铝合金和含稀土元素的合金，它们的强化机制主要是尺寸效应引起的固溶强化。在所有合金中都观察到了明显的蠕变合金化强化效果，尤其是含Y的合金。镁合金和其他合金的无量纲归一化蠕变速率的比较。基于滑动控制蠕变的物理模型，对镁合金和铝基合金的观察蠕变速率和报告的蠕变速率进行归一化。在蠕变激活能与扩散激活能相近的温度下，镁铝合金的归一化蠕变速率明显低于铝镁合金，归一化蠕变速率的比值在10~100之间变化。改变和控制镁合金的份额模数有望成为提高镁合金蠕变强度的一种很有前途的方法。镁合金具有良好的抗蠕变性能，是一种性能优良的耐光耐热材料。实验研究了全片层TiAl合金的组织控制及其力学性能。

Effects of solute atoms on high temperature creep characteristics in magnesiurn alloys.Creep behavior and its characteristics are experimentally investigated in magnesium alloys, and the characteristics are compared by means of minimum creep rates. The examined alloys are magnesium-aluminum alloys whose strengthening mechanism is expected to be solution strengthening mainly caused by size effect, and alloys, which contain rare-earth element. Obvious strengthening effects by alloying in creep are observed in all alloys, especially in alloys, which contain yttrium. Combined solution strengthening effects may operate in solid solution alloys.Comparison of non-dimensional normalized creep rates in magnesium and other alloys.Observed creep rates and reported creep rates in magnesium-based alloys and aluminum-based alloys are normalized based on physical models of glide-controlled creep. The normalized creep rates in magnesium- aluminum alloys are obviously lower than that in aluminum-magnesium alloys, and the ratio in normalized creep rate varies in range 10 to 100, at the temperatures where the activation energies of creep are similar to that for diffusion. Modification and control of share modulus in alloys are expected to be one promising method to improve creep strength in magnesium alloys. Magnesium show good creep resistance and its alloys are considered as superior light heat-resistant materials.Structure control in fully lamellar TiAl alloys and its mechanical properties are experimentally examined.