Abstract

Externally physical fields such as stress field, electric field and magnetic field have been demonstrated influence the equilibria and kinetics of solid-state transformations in metals and alloys. This review focuses on the effects of externally physical fields on the aging precipitation of aerospace Al alloys including 2xxx Al-Cu alloys, 7xxx Al-Zn-Mg alloys as well as the advanced Al-Li alloys. While the η’ phase in Al-Zn-Mg alloy and the T₁ phase in Al-Li alloy showed no obvious stress-orientating effect, the precipitation of θ’ phase in Al-Cu alloy showed obvious stress-orientating effect depending on the applied stress direction. Regarding precipitation kinetics, aging under stress field, electric field and magnetic field all can enhance the aging precipitation of aerospace Al alloys. The understanding of the effects of externally physical field on the aging precipitation in Al alloys is very preliminary. It appears that while the stress field acts on the thermally activated transformation, the athermal effect associating with electromigration of electromagnetic field has been considered responsible for the enhanced aging precipitat ion.

摘要

应力场、电场和磁场等外部物理场已被证明会影响金属和合金中固态转变的平衡和动力学。本文重点研究了外部物理场对航空航天铝合金时效析出的影响，包括2 xxx Al-Cu合金、7 xxx Al-Zn-Mg合金以及先进的Al-Li合金。而Al-Zn-Mg合金中的η'相和T ₁Al-Li合金中θ'相的析出没有表现出明显的应力取向效应，而Al-Cu合金中θ'相的析出则表现出明显的应力取向效应，这取决于所施加的应力方向。从析出动力学来看，应力场、电场和磁场下的时效均能促进航空航天铝合金的时效析出。对于外部物理场对铝合金时效析出的影响的认识还很初步。看来，虽然应力场作用于热激活转变，但与电磁场电迁移相关的非热效应被认为是增强老化沉淀的原因。