单道次轧制变形对Hastelloy C-276合金晶界特征分布的影响

采用电子背散射衍射(EBSD)技术研究了固溶处理的Hastelloy C-276合金经2.5%~90%变形后在1150℃退火15min的晶界特征分布(GBCD)。结果表明,在5%变形条件下,总的特殊晶界比例最高为67.1%,其中特殊晶界主要是Σ3晶界,Σ9和Σ27晶界比例较低。当变形量小于15%时,晶粒组织处于回复或部分再结晶,晶粒组织粗大,特殊晶界比例随变形量变化较大。在此阶段,回复或部分再结晶有利于晶界的迁移,从而产生更多特殊晶界。当变形量大于15%后,随变形的增加,晶粒组织细小,特殊晶界比例在50%左右。这是由于晶粒发生完全再结晶后,大角度晶界增多,不利于特殊晶界的形成。因而,Hastelloy C-276合金晶界特征分布优化变形范围应小于15%,更有利于特殊晶界的产生和分布。

The effect of Single-pass rolling deformation on character distributions for Hastelloy C-276 alloy grain boundary

Grain boundary character distributions(GBCD)in the solid solution Hastelloy C-276 alloy after cold rolled from 2.5%to 90%reduction and annealed at 1100℃for 15min has been investigated by means of electron back scatter diffraction(EBSD).The results show that the proportion of total special boundary is up to 67.1%,of which the most special boundary is Σ3 boundary,the other Σ9 and Σ27 boundaries proportion are lower.When the deformation is less than 15%,the gain size is larger during the recovery and particular recrystallization,while the deformation has an effect on the proportion of special boundary.In the state,it can promote the grain boundary migration,and then more special boundaries are produced.When the deformation is more than 15%,the grain size is refined,and the proportion of special boundary is nearly 50%.Due to the grain microstructure's recrystallization,it will generate more large angle boundaries and restraint the special boundary formation.Therefore,the optimized deformation range of character distributions for Hastelloy C-276 alloy grain boundary should be selected in less than 15%,which is more conducive to the generation and distribution of special grain boundaries.