(1. 中南大學 材料科學與工程學院，長沙 410083；
2. 中南大學 有色金屬材料科學與工程教育部重點實驗室，長沙 410083)
摘 要: 采用維氏硬度、室溫拉伸性能測試、金相顯微分析技術(shù)、透射電子顯微分析等手段，研究Mg含量對Al-Cu-Mg-Ag耐熱鋁合金的組織和性能的影響。結(jié)果表明：隨著Mg含量的增加，合金的時效響應速率加快，峰時效時間提前，且峰值硬度先增大后減小，在Cu/Mg摩爾比接近6時峰值硬度達到極大值；合金的抗拉強度和屈服強度先上升后下降，塑性則先降低后提高，但總體保持在較高水平；Mg含量(質(zhì)量分數(shù))為0.4%和0.8%時，合金的主要強化相為Ω相和少量θ′相，Mg含量為1.2%的合金主要強化相為Ω相和S′相，隨著Mg含量的增加，Ω相的體積分數(shù)增大，尺寸減小，分布更加均勻，但當Mg含量增大到1.2%時，Ω相的體積分數(shù)有所減小。
關(guān)鍵字: Al-Cu-Mg-Ag合金；顯微組織；力學性能
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Nonferrous Materials Science and Engineering, Ministry of Education,
Central South University, Changsha 410083, China）
Abstract:The effects of Mg content on the mechanical properties and microstructures of Al-Cu-Mg-Ag alloy were studied by Wicker hardness test (HV), room temperature tensile properties, optical microscopy (OM) and transmission electron microscopy (TEM). The results show that with the increase of Mg content, the aging response rate is accelerated, the peak aging is advance, and whereas the peak hardness increases at first and then decreases which reaches its maximum when the Cu/Mg ratio closes to 6. With the increase of Mg content, the yield strength and the tensile strength increase first and then decrease, while the plasticity is just the opposite, but it maintains at a high level. The main strengthening phases are Ω phase and a bit of θ ′ phase when the Mg content (mass fraction) is 0.4% or 0.8%, but translate to Ω phase and S′ phase when the Mg content is 1.2%. The volume fraction of Ω phase increases with the increase of Mg content, the size decreases and it distributes more uniform. However, the volume fraction of Ω phase decreases to some extent when the Mg content is 1.2%.
Key words: Al-Cu-Mg alloy; microstructure; mechanical property
