2219铝合金粗大第二相粒子破碎机理

Crushing mechanism on coarse second-phase particles for 2219 aluminum alloy

对多向锻造后的2219铝合金进行了高温和中低温压缩试验,研究了2219铝合金长条状和等轴状第二相粒子的破碎行为,揭示了其破碎细化机理。研究结果显示,高温(T=510℃)双向压缩时,长条状粒子塑性较好,变形时被压弯,当超过弯曲极限时,粒子发生破裂;当T下降至240℃时,长条状粒子脆性增加,大量粒子被脆性折断,细化效果显著提升,粒子主要呈等轴状,等轴状粒子占总结晶相的面积分数从高温时的64%增加至79%。等轴状粒子破碎难度大,高温压缩变形时,主要借助位错的形成和迁移行为实现粒子外围逐渐溶解,尺寸减小;中低温压缩变形时,基体中的位错回复和迁移较慢,易在粒子附近塞积和缠绕,等轴状粒子主要借助位错引起的基体强化作用实现破碎,破碎效果提升。

The compression tests at high temperature and medium-low temperature of 2219 aluminum alloy after multi-directional forging were carried out,the crushing behavior of elongated and equiaxed second-phase particles for 2219 aluminum alloy was investigated,and the crushing and refining mechanism was revealed.The research results show that when compressed bidirectionally at high temperature(T=510 C),the elongated particles have better plasticity,and the particles are bent when deformed and break when the bending limit is exceeded.When T drops to 240 C,the brittleness of the elongated particles increases,and a large number of particles are broken by brittleness to improve the refining effect significantly.The particles are mainly equiaxed,and the area fraction of equiaxed particles to the total crystal phase increases from 64%at high temperature to 79%.Due to the difficulty of breaking equiaxed particles,when high temperature compression deformation,the particle periphery is gradually dissolved and the size is reduced mainly through the formation and migration behaviors of dislocation,when medium-low temperature compression deformation,the recovery and migration of dislocation in the matrix are slow and easy to accumulate and entangle near the particles,the equiaxed particles mainly rely on the matrix strengthening effect caused by dislocation to achieve crushing and improve the crushing effect.