预变形对Al-Cu-Li-Mn-Zr合金的第二相析出及力学性能的影响

摘要

The effect of pre-deformation on the precipitation behavior and mechanical property of Al-Cu-Li-Mn-Zr alloy were investigated by Vickers hardness measurement,room-temperature tensile test and transmission electron microscopy (TEM) characterization.The results showed that in the peak aged Al-Cu-Li-Mn-Zr alloy without pre-deformation,the T1 and θ'phases were usually dominant,while the amount of x phase was very limited.When this alloy was subjected to the pre-deformation prior to aging,the formation of T1 was promoted,and the nucleation of θ'was inhibited,while there was little influence on the formation of x phase.Therefore,the T1 phase was primary precipitate in the aged alloy with pre-strain.With the increase of pre-strain,although the diameter of the T1 precipitates became smaller,the thickness and volume fraction of them kept almost the same.In addition,when larger pre-strain was applied,the alloy showed higher strength and lower plasticity.%采用维氏硬度、常温拉伸及透射电子显微镜等测试手段,研究了不同预变形状态对Al-Cu-Li-Mn-Zr合金中第二相析出行为及力学性能的影响.结果表明,未经预变形的峰值时效态Al-Cu-Li-Mn-Zr合金的析出相有T1 (Al2CuLi)相、θ'(Al2Cu)相,且存在极少量的x (Al5Cu6Li2)相.预变形的引入使T1相的析出量显著增加,同时抑制了θ'相的形成,但对x相的析出量的影响却较小.由此可知,经预变形的合金在峰值时效态的析出相以细小弥散的T1相为主.经定量统计可知,预变形量越大,作为主要析出相的盘片状T1相的直径越小,但厚度及体积分数几乎保持不变.此外,随着预变形量的增大,峰值时效态合金的屈服强度和抗拉强度升高,塑性降低.