用正电子湮没方法探测铜基合金中的有序无序转变

The Detection of Order-Disorder Transformation for Cu-Zn-Al Alloy by Positron Annihilation

用正电子湮没Doppler展宽能谱,结合金相显微镜和示差热分析方法分析了一系列在不同温度处理然后淬入室温水中的Cu-23at％Zn-10at％Al合金试样。结果表明:该合金在900℃处理后,降温过程中分别于700℃～600℃,550℃～500℃,300℃～250℃,发生了相变,第一个是α相变,第二和第三个是无序—有序转变。正电子湮没方法对该合金中的α相变不敏感,但对该合金中的有序—无序转变敏感。

A series of the specimens of Cu - 23at%Zn - 10at% Al shape memory alloy quenched from different high temperature into water at room temperature have been measured by positron Doppler broadening technique associated with optical microscopy and differential termal analysis. The measurements indicate that the alloy undergoes three transitions during cooling that exist between 700℃, and 600℃, between 550℃ and 500℃, and between 300℃ and 250℃ , respectively. The former is an alpha - phase transition, The latter two are order - disorder ones; Positron annihilation technique is sensitive to the order- disorder transitions, but not to the alpha - phase transition which is very easy observed by means of optical and transmission election microscope, And it is shown that positron annihilation technique is a good tool to study microstructures in metallic materials.