急冷Ag-Ge二元系合金的相关系

用X射线衍射和热学分析的方法研究了急冷(冷却速度约为10⁴K/s)Ag-Ge二元系样品的相关系。由于急冷Ge在Ag中的溶解度由平衡下的1.5at％扩展到8at％。在Ge含量为8—23at％的样品中,除含Ge在Ag中的过饱和固溶体和Ge外,还有一个具有与Ag基过饱和固溶体相同成分,不同堆垛形式的亚稳相,属A3型六角密排结构,点阵常数a=2.893±0.010?,c=4.720±0.010?,c/a=1.632。用DuPont公司1090系列的差示扫描量热仪(DSC)研究了过饱和固溶体和关键词：

A STUDY ON PHASE RELATIONS OF RAPIDLY QUENCHED ALLOYS IN Ag-Ge SYSTEMS

The phase relations and thermodynamic stabillity of metastable phases in rapidly quenched Ag-Ge alloys have been studied by means of DTA, DSC and X-ray powder diffraction techniques. Solubillity of Ge in Ag is extended from 1.5 at% Ge to 8 at% Ge, when cooling speed of alloy is approximately 10⁴ K/s. Except supersaturated solid solution of Ge in Ag and Ge, there also exists a metastable phase, which has the hexagonal close-packed structure (hep) with lattice parameters a=2.893±0.010 ?, c=4.720±0.010 ?, c/a=1.632. For 20 at% Ge alloy, the activation energy of hep phase transition and supersaturated solution desolvation are 93 kJ/mol and 102 kJ/mol respectively. The nature and transition mechanism of the metastable phases are discussed.
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