论文部分内容阅读
采用力学性能测试、DSC及TEM研究了预变形对Al-Mg-Si-Cu合金析出行为的影响.结果表明,在慢速率升温过程中,预时效态合金GP区溶解速率均随预变形量的增加而降低,利用Avrami-Johnson-Mehl方法求得经0,5%和15%预变形后合金的GP区溶解激活能分别为137.1,189.5和141.3 k J/mol;若合金经不同预变形后直接进行185℃,20 min烤漆硬化,预变形可有效促进沉淀相析出,提高烤漆硬化增量,最高达160 MPa,不过预变形量大于10%时合金烤漆硬化增幅减缓;此外,经预变形处理后烤漆态合金的GP区溶解速率在一定温度下均较低,但高于某一温度后,相应的GP区溶解速率均高于未经预变形处理,最终获得的ln[(d Y/d T)f/f(Y)]-1/T曲线甚至会出现高激活能向低激活能转化现象;不过随预变形量增加,β″相析出激活能不断降低,析出速率不断增加.
The effect of pre-deformation on the precipitation behavior of Al-Mg-Si-Cu alloy was studied by mechanical properties test, DSC and TEM.The results showed that the dissolution rate of GP zone in the pre-aging effect alloy decreased with the pre-deformation The GP activation energy of the alloys prepared by 0, 5% and 15% pre-deformation was 137.1, 189.5 and 141.3 kJ / mol, respectively, according to the Avrami-Johnson-Mehl method. After 185 ℃ for 20 min, the pre-deformation can effectively promote precipitation precipitation and increase the increment of paint hardening up to 160 MPa. However, the hardening of alloy paint slows down when the pre-deformation is greater than 10%. In addition, After the treatment, the dissolution rate of the GP zone of the painted alloy was lower at a certain temperature, but higher than a certain temperature, the dissolution rate of the corresponding GP zone was higher than that without pre-deformation treatment, and the final ln [(d Y / dT) f / f (Y)] - 1 / T curve even shows the phenomenon of high activation energy to low activation energy. However, with the increase of pre-deformation, the activation energy of β "phase precipitation declines continuously and the precipitation rate increases.