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对Al-5Cu铝合金在时效过程中施加弹性加载,并采取透射电镜、热分析研究外应力时效作用下θ″析出相的形态和析出行为。结果表明:在50 MPa的外力作用下,在453 K时效6 h后的析出相尺寸是19.83 nm,小于其常规时效(453 K,6 h)的尺寸28.79 nm。热分析结果揭示施加应力后时效析出过程得到促进,同时析出激活能结果表明外应力作用使得激活能下降10%。第一性原理计算结果发现,外应力作用使得析出相与基体的界面能下降6%;结合经典形核相变理论分析讨论,临界形核功受到外应力作用下降19%,从而引起了析出相形态和析出行为的改变。
The elastic deformation of Al-5Cu aluminum alloy during aging was investigated by TEM and TEM, and the morphology and precipitation behavior of θ "precipitated phase under external stress aging were investigated. The results show that under the action of external force of 50 MPa, After 6 h of aging, the precipitated phase size is 19.83 nm, which is smaller than the 28.79 nm of its conventional aging (453 K, 6 h). The thermal analysis results show that the precipitation process is accelerated after the stress is applied and the activation energy shows that the external stress The activation energy can be reduced by 10% .The results of the first-principles calculation show that the external stress reduces the interfacial energy between the precipitated phase and the matrix by 6% .Based on the analysis and discussion of the classical nucleation phase transformation theory, the critical nucleation energy is reduced by the external stress 19%, which led to changes in precipitated phase morphology and precipitation behavior.