Si对Al-Er合金时效行为及析出相微观结构的影响

Effect of Si on aging behavior and precipitated phase structure of Al-Er alloy

通过显微硬度计、电导率测量仪和透射电镜等研究了添加不同含量的Si对Al-Er合金在不同温度下的时效行为及析出相微观结构的影响。结果表明:Si含量在0.15%和0.25%时,合金时效过程中无明显时效强化现象,Si含量为0.50%时合金时效强化效果最佳,275℃等温时效72 h时达到硬度峰值(约为40.3 HV0.1),随后迅速下降出现过时效。在时效过程中,从Al-0.04Er-0.50Si合金基体中脱溶出的溶质原子最多,形成更多析出相,提高了合金的硬度,电导率增幅达4.0%IACS。Al-0.04Er-0.50Si合金经过等温时效处理后析出相数密度大大提高,并且析出相结构不再是Al-Er合金中L1_(2)结构的Al_(3)Er相而是转变为PuAl_(3)(HT)型结构的ErAl_(2.8)Si_(0.2)(τ1)相。

Effect of adding different amounts of Si on aging behavior and precipitated phase structure of the Al-Er alloy at different temperatures was studied by means of microhardness testers,conductivity testers and transmission electron microscopy.The results show that there is no obvious aging strengthening phenomenon during the aging process of the alloy when the Si content is 0.15% and 0.25%.The aging strengthening effect of the alloy is the best when the Si content is 0.50%,the hardness peak(about 40.3 HV0.1)is reached after 72 h of isothermal aging at 275℃ and then rapidly decreases,and over aging occurs.During the aging,the desolvated solute atoms are the most from the Al-0.04Er-0.50Si alloy matrix,forming more precipitated phases,improving the hardness of the alloy,and increasing the conductivity by 4.0%IACS.After isothermal aging treatment,the number density of precipitated phases in the Al-0.04Er-0.50Si alloy is greatly increased,and the precipitated phase structure is no longer Al3Er phase with L1_(2) structure in the Al-Er alloy,but ErAl_(2.8)Si_(0.2)(τ1)phase with PuAl_(3)(HT)type structure.