(中南大学 粉末冶金国家重点实验室，长沙 410083)
摘 要: 采用金相显微镜、扫描电镜、透射电镜与力学性能测试等方法，研究Ag与La对Al-5.3Cu-0.8Mg(质量分数，%)合金的显微组织与时效特性的影响。结果表明：添加0.1La降低铸态Al-5.3Cu-0.8Mg-(0.6Ag)合金的晶粒尺寸；但并不能明显提高挤压态Al-5.3Cu-0.8Mg合金的时效硬化；添加0.6Ag能提高挤压态Al-5.3Cu-0.8Mg合金的时效硬化能力与抗拉强度，降低185℃时的峰时效时间。这是由于Ag的添加改变基体合金的时效析出相，合金的主要强化相由片状Ω相和少量θ′ 相组成。同时，添加0.6Ag与0.1La有助于提高Al-5.3Cu-0.8Mg合金中Ω相的体积分数，最终使其力学性能得到进一步改善。
关键字: 铝合金；Ag；La；显微组织；力学性能
（State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract:A series of Al-5.3Cu-0.8Mg (mass fraction, %) based alloys with different Ag and La contents were investigated by optical microscope(OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and mechanical properties testing. The results show that adding 0.1La refines the grains of as-cast Al-5.3Cu-0.8Mg-(0.6Ag) alloys, but does not improve the hardness of the extruded Al-5.3Cu-0.8Mg alloys. Adding 0.6Ag can increase the hardness and tensile strength of extruded Al-5.3Cu-0.8Mg alloys and decrease the peak-aging time at 185 ℃. The coherent plate-like Ω phase and a small amount of θ′ phase are the predominant hardening phases of the Al-5.3Cu-0.8Mg-0.6Ag alloys at peak-aged stage at 185 ℃. Moreover, adding 0.1La into Al-5.3Cu-0.8Mg-0.6Ag alloy decreases the size and improves the density and the thermal stability of Ω phase, and then improves the mechanical properties of the alloy.
Key words: aluminum alloys; Ag; La; microstructure; mechanical properties
