高压扭转诱导新型Al-Zn-Mg-Cu合金第二相回溶

Dissolution of secondary phase in novel Al-Zn-Mg-Cu alloy reduced by high pressure torsion

分别在380和400℃下对铸态Al-Zn-Mg-Cu合金进行高压扭转实验,随后对变形试样进行温度为100℃、时间为2～10h的时效实验。采用X射线衍射仪、扫描电镜和维氏硬度分析Al-Zn-Mg-Cu合金在高压扭转变形过程中第二相形貌与含量变化以及时效过程中形变试样硬度的变化。结果表明:在高压扭转变形中,合金中第二相破碎、细化并回溶到基体中形成过饱和固溶体,第二相的回溶程度随着温度的升高和变形量的增加而增加。变形试样经100℃时效处理后,硬度随时效时间的增加先上升后下降。试样回溶程度越高,时效达到峰值所需的时间越短。

As-cast Al-Zn-Mg-Cu alloy was deformed by high pressure torsion at 380℃and 400℃,respectively,and then proceeded aging treatment at 100℃for 2?10 h.The changes of morphology and content of the secondary phase of Al-Zn-Mg-Cu alloy during high pressure torsion as well as the hardness of the samples deformed by high pressure torsion under aging were studied by X-ray polycrystalline diffraction,scanning electron microscopy and Vickers hardness.The results show that the secondary phase is broken and dissolved into matrix,and then form the supersaturated solid solution,the dissolution degree of the secondary phase increases with increase of the temperature and deformation.The hardness of the samples deformed by high pressure torsion increases and then decreases with the increase of the aging time during aging at 100℃.The higher the dissolution degree,the shorter the time reaching the peak of the samples during aging.