(中南大學(xué) 粉末冶金國(guó)家重點(diǎn)實(shí)驗(yàn)室，長(zhǎng)沙 410083)
摘 要: 采用金相顯微鏡、掃描電鏡、透射電鏡與力學(xué)性能測(cè)試等方法，研究Ag與La對(duì)Al-5.3Cu-0.8Mg(質(zhì)量分?jǐn)?shù)，%)合金的顯微組織與時(shí)效特性的影響。結(jié)果表明：添加0.1La降低鑄態(tài)Al-5.3Cu-0.8Mg-(0.6Ag)合金的晶粒尺寸；但并不能明顯提高擠壓態(tài)Al-5.3Cu-0.8Mg合金的時(shí)效硬化；添加0.6Ag能提高擠壓態(tài)Al-5.3Cu-0.8Mg合金的時(shí)效硬化能力與抗拉強(qiáng)度，降低185℃時(shí)的峰時(shí)效時(shí)間。這是由于Ag的添加改變基體合金的時(shí)效析出相，合金的主要強(qiáng)化相由片狀Ω相和少量θ′ 相組成。同時(shí)，添加0.6Ag與0.1La有助于提高Al-5.3Cu-0.8Mg合金中Ω相的體積分?jǐn)?shù)，最終使其力學(xué)性能得到進(jìn)一步改善。
關(guān)鍵字: 鋁合金；Ag；La；顯微組織；力學(xué)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
