高温退火过程中铅合金晶界特征分布的演化

EVOLUTION OF GRAIN BOUNDARY CHARACTER DISTRIBUTIONS IN Pb ALLOY DURING HIGH TEMPERATURE ANNEALING

应用电子背散射衍射(EBSD)和取向成像显微(OIM)技术,对经过不同形变及热处理的铅合金样品晶界特征分布(GBCD)进行了分析,研究结果表明：进行合适的冷轧后在高温(0．9T_m)短时间退火,可将铅合金的低∑(∑≤29)重位点阵(CSL)晶界比例提高到70％以上,回复过程中形成∑1晶界的同时,也出现了∑3晶界,∑3晶界在再结晶的初期过程中得到发展,这是提高低∑CSL晶界比例的主要原因,在低∑CSL晶界比例较高时,从OIM中很容易找到由三条CSL晶界构成的界角,该界角的三个晶粒之间存在特定的取向关系。

Grain boundary character distributions （GBCD） in Pb alloy after thermomechanical treatments were analyzed by electron back scatter diffraction （EBSD） and orientation imaging microscopy （OIM）. The frequencies of low ∑ coincidence site lattice （CSL） grain boundaries in Pb-alloy can be enhanced to more than 70% after proper cold rolling combined with annealing at high temperature （0.9Tm） for a very short period of time. Together with ∑1 boundaries, the ∑3 boundaries appeared during recovering. The development of ∑3 boundaries in the primary stage of recrystallization is the main reason for enhancing the frequencies of low ∑CSL grain boundaries. Triple junctions contained three CSL grain boundaries could be easily found in the OIM map of the specimen with high frequencies of low ∑CSL grain boundaries, and there are specific orientation relationships among the grains assembled by the triple junctions.