摘要
采用透射电镜、电导率和维氏硬度测定法,研究了7055铝合金三级时效过程中一级时效时间和二级时效条件对合金组织和性能的影响。结果表明,第一级120℃时效0.5 h即可对第二级190℃时效起预形核处理作用,但继续延长第一级时效时间对三级时效后合金的电导率和硬度影响不大,第二级时效时快速加热有利于同时提高合金的硬度和电导率,第三级120℃24 h时效具有同时提高合金硬度和电导率的作用,使合金晶界和基体析出相粗化,但对基体析出相的密度影响不大。经合适的三级时效处理(如120℃0.5 h^24 h+盐浴190℃10 min,W.Q+120℃24h),7055合金获得的硬度和电导率比T6状态的更高。
Three-step aging treatments of 7055 aluminium alloy have been investigated by means of test of electrical conductivity,hardness and TEM. The results show that the first-step aging at 120℃ for 30min can play a pre-nucleating part in precipitateon of second-step aging at 190℃, when the time of first-step aging exceeds 30 min , its prolongation do not distinctly influence the electrical conductivity and hardness of three-step aged 7055 alloy. The electrical conductivity and hardness of 7055 alloy can be simultaneously increased by rapidly increasing to temperature of second-step aging or utilizing the third-step aging at 120℃ for 24h. Thethird-step aging can make gain boundary and matrix precipitates growing, but do not distinctly influence the density of matrix precip-itates. Hardness and electrical conductivity of 7055 alloy treated by appropriate third- step aging treatment （e. g. 120 ℃ 0.5 h - 24 h ＋ salt bath 190℃ 10 min, W.Q. ＋ 120℃ 24 h） are higher than that of T6 condition.
出处
《轻合金加工技术》
CAS
北大核心
2006年第5期40-43,54,共5页
Light Alloy Fabrication Technology
关键词
7055铝合金
三级时效
电导率
硬度
7055 aluminium alloy
three-step aging
electrical conductivity
hardness
