Development of Light-Weight Materials having Higher Performance at high Temperature Controlled by hexagonal-platelet Equilibrium Phase

为了改善Al-Mg-Si合金的高温力学性能，用透射电子显微镜和硬度测试方法研究了添加铜和/或银的20种合金的析出相和时效行为。在添加了铜和/或银的合金中，在673K时效时发现了六方晶片。这是有关该板块的首次报道。这种薄片与铝基具有如下的晶体取向关系：{111}_&lt；Al&gt；//{L11}_&lt；&lt；110&gt；_&lt；Al&gt；//&lt；110&gt；_&lt；hexβ&gt；.，β&gt；这种薄片的晶格和化学成分与正常的β-Mg_2Si相同。然而，通过EDS分析，银可能包含在这一相中。这些在423K时效的铜和银合金表现出比只加铜或银的合金更高的延伸率和强度。这一结果已被提交给日本专利。

For the purpose to improve mechanical property at higher temperature in Al-Mg-Si alloys, precipitates and aging behavior of20alloys with Cu and/or Ag addition have been investigated by TEM and hardness test. The hexagonal platelet has been discovered in alloys with Cu and/or Ag addition aged at673K. This is the first report about such plate. This platelet has the crystallographic orientation relationship with the Al-matrix as follows: {111}_<Al>//{l11}_<hexβ>,<110>_<Al>//<110>_<hexβ>. This platelet has the same crystal lattice and chemical composition as the normal β-Mg_2Si. However, Ag could be included in this phase by EDS analysis. These alloys with Cu and Ag aged at423K have shown higher elongation and strength than that with just Cu or Ag. This result has been proposed to the Japanese Patent.