均匀化前预处理对Al-Zn-Mg-Cu合金中含V相析出及再结晶的影响

Effects of pretreatments before homogenization on precipitation of V containing dispersoids and recrystallization in Al-Zn-Mg-Cu alloy

用透射电子显微镜（TEM）及扫描电镜电子背散射（EBSD）技术,研究了均匀化前250℃~400℃的预处理对w（V）=0.11%的超高强Al-Zn-Mg-Cu合金中Al21V2弥散相析出行为及变形后再结晶抗力的影响,并计算了V在铝基体中的扩散常数和扩散距离。结果表明,铸锭均匀化处理过程形成Al21V2弥散相,并在晶界附近形成明显的无析出区,其宽度基本不受均匀化处理前预处理的影响;在普通均匀化处理前预处理能明显提高Al21V2弥散相的密度、减小其尺寸;在铝基体中,V在300℃及400℃的扩散常数分别为9.81×10-31m2/s、5.32×10-24m2/s。在300℃预处理合金能获得尺寸最小、密度最高的Al21V2弥散相,而且其热变形后再结晶抗力最大。

The effects of pretreatment at 250℃- 400℃ before homogenization on precipitation behavior of V containing dispersoids and recrystallization resistance in super-high strength Al-Zn-Mg-Cu alloy with w（ V） = 0. 11% were investigated by using transmission electron microscope（ TEM） and electron backscattered diffraction（ EBSD） techniques,the diffusion coefficient and diffusion distance of V in Al matrix were calculated as well. The results show that Al21V2 dispersoids are precipitated during homogenization and the precipitatefree zones of these dispersoids are formed near the graon boundaries,the widths of the precipitate-free zones are not affected when pretreatments applied before homogenization. Pretreatments before homogenization significantly increase the number density and decrease the size of Al21V2 dispersoids. The diffusion coefficient of V in Al matrix at 300℃ and 400℃ are9. 81 × 10- 31m2/ s and 5. 32 × 10- 24m2/ s,respectively. Furthermore,the finest size and highest number density of Al21V2 dispersoids and highest recrystallization resistance were obtained when pretreated at 300℃ before homogenization.