不同温度轧制Pb-Ca-Sn-Al合金高温退火后的晶界特征分布

GRAIN BOUNDARY CHARACTER DISTRIBUTIONS OF Pb-Ca-Sn-Al ALLOY ANNEALED AT ELEVATED TEMPERATURE AFTER ROLLING AT DIFFERENT TEMPERATURES

采用电子背散射衍射(EBSD)技术研究了不同温度轧制的Pb-0.09Ca-1.5Sn-0.026Al(质量分数,%)合金经后续270℃/10 min退火后的晶界特征分布(GBCD),结果表明:经室温和液氮(-196℃)轧制的样品中出现了比较多的∑3,∑9和∑27特殊晶界,∑3品界比例超过了60%,(Σ9+∑27)晶界比例超过了12%,并且特殊晶界有效地阻断了一般大角度晶界的网络连通性,表明合金的GBCD破优化;在100℃轧制的样品中特殊晶界比例较少,Σ3品界比例在30%左右,(∑9+∑27)晶界比例在3%左右,特殊晶界不能有效地阻断一般大角度晶界的网络连通性,合金的GBCD没有被优化,通过基于EBSD的单一截面迹线法对共格和非共格Σ3品界进行了区分测定,显示被优化的晶界特征分布中,非共格Σ3品界是主要部分。

The grain boundary character distributions （GBCD） of Pb-0.09Ca-1.5Sn-0.026Al alloy （mass fraction, %） rolled at different temperatures and then annealed （270 ℃/10 min） were investigated by means of electron back scatter diffraction （EBSD）. The results showed that special boundaries such as ∑3, ∑9 and ∑27 were largely populated in the specimens which were rolled at room temperature and -196 ℃, the fractions of ∑3 and （∑9＋∑27） boundaries exceeded 60% and 12%, respectively. The connectivity of general high angle boundaries （HABs） network was interrupted substantially by special boundaries, which indicated the optimization of GBCD. However, much lower fractions of special boundaries were developed in the specimen rolled at 100 ℃, and the connectivity of general HABs network was not interrupted significantly, implying the GBCD was not optimized. Single section trace analysis based on EBSD technique revealed that the incoherent ∑3 boundaries are major part of ∑3 boundaries in the optimized GBCD.