预变形对Al-Cu-Li-(Mg-Ag)合金时效析出行为的影响

Effects of pre-deformation on the precipitation behavior of Al-Cu-Li-(Mg-Ag)alloy during artificial aging

通过采用维氏硬度测试、透射电子显微镜(TEM)、差示扫描量热法(DSC)等手段研究了预变形对Al-Cu-Li及Al-Cu-Li-Mg-Ag两种合金时效析出行为的影响。结果表明:在Al-Cu-Li合金中,峰时效后θ'相的析出占据主导,并且通过预变形引入位错有利于Al-Cu-Li合金时效后θ'相的析出,而对T1相几乎没有促进作用;添加微量Mg、Ag元素后,Al-Cu-Li-(Mg-Ag)合金峰时效后的析出相转变为T1相并占据主导,θ'相较少;Al-Cu-Li-(Mg-Ag)合金经预变形时效后T1相和θ'相的数量密度均有所增加,即预变形同时促进了T1相和θ'相的析出;在Ɛ=0~3%预变形范围内,T1相的数量密度随着预变形量的增加而增大,并且T1相的尺寸也变得更加细小和均匀,进而使合金获得更优异的性能。

The effect of pre-deformation on the precipitation behavior of Al-Cu-Li and Al-Cu-Li-(Mg-Ag)alloys during artificial aging(RA)was studied by the Vickers hardness test,transmission electron microscopy(TEM)and differential scanning calorimetry(DSC).The results showed that the precipitation of theθ'phase was the main phase after peak-aging in Al-Cu-Li alloy.Moreover,the dislocation caused by pre-deformation was beneficial to the precipitation ofθ'phase in Al-Cu-Li alloy after aging but had little effect on the T1 phase.For the Al-Cu-Li-(Mg-Ag)alloy,the precipitation of the T1 phase andθ'phase was promoted by pre-deformation during RA.After the addition of trace Mg and Ag solute elements,the precipitation phase of Al-Cu-Li-Mg-Ag alloy was mainly the T1 phases after peak-aging,with fewerθ'phases.The number density of the T1 phases andθ'phases increased after the pre-deformation aging of the Al-Cu-Li-(Mg-Ag)alloy,that is,the pre-deformation promoted the precipitation of the T1 phases andθ'phases simultaneously.Within the pre-deformation range ofƐ=0~3%,the number density of the T1 phases increased with the increment of pre-deformation,and their size was also becoming more uniform and smaller.Thus,the alloy could obtain more excellent mechanical properties.