Hastelloy C-276合金中Σ9和Σ27晶界与随机晶界网络连通性的关系

The relationships between the Σ9 and Σ27boundaies and the connectivity of random boundary in Hastelloy C-276

摘要:

Hastelloy C-276合金经冷轧10%后进行1100℃不同时间的退火热处理。采用EBSD技术对Σ3_n晶界(n=1、2、3)晶界比例进行统计并对随机晶界网络连通性进行表征。结果表明,随着退火时间的延长,Σ3晶界比例基本保持不变,而Σ9和Σ27晶界比例却出现较大幅度的变化,并且其峰值点都出现退火15min条件下。此刻,相应的随机晶界网络连通性被有效阻断。这是由于非共格Σ3晶界的存在,产生了更多的Σ9和Σ27晶界,并且使得这些特殊晶界连接到随机晶界网络当中。而采用Σ(9+27)/Σ3比值可以更好的表征随机晶界网络的连通性。

Abstract:

Hastelloy C-276 was subjected to 10% deformation and annealed at 1100°C for different times. The fractions of Σ3_n(n=1,2,3) boundaries and the connectivity of random boundary networks were characterized by electron back-scatter diffraction (EBSD). The results showed that the Σ3 boundary fraction is hardly increasing during annealing time. Instead, the fractions of Σ9 and Σ27 boundaries have a dramatic change with annealing times, whose peaks are arisen at annealed 15min. Meanwhile, the corresponding connectivity of random boundary network is effectively disrupted. This can be attributed to the incoherent Σ3 boundary producing more Σ9 and Σ27 boundaries and incorporating those boundaries into the random boundary networks. Actually, the connectivity of random boundary networks can be definitely identified by Σ(9+27)/Σ3 radio.