GH49合金锻造叶片局部粗晶的研究

本文论述了GH49合金锻造叶片局部粗晶形成的主要原因是临界变形。临界变形粗晶形成的机理是原始晶粒的直接长大,临界变形区晶粒长大的最初驱动是晶界两侧的畸变能差。为消除临界变形粗晶,一方面可以通过控制变形条件尽可能缩小临界变形区的范围;另一方面,锻后立即趁热进行短时间的退火处理,减小临界变形区的畸变能差,以控制粗晶区晶粒尺寸,实际效果是令人满意的。

RESEARCH ON THE ORIGIN OF LOCALIZED COARSE GRAINS IN FORGED GH49 ALLOY BLADES

The origin of localized coarse grains in forged GH49 alloy blades and some approaches of their prevention are studied in this paper. In authors' opinion, the formation of localized coarse grains is primarily due to critical deformation. The mechanism of the formation of coarse grains after critical deformation is the direct growth of some original grains at the expense of others.The primary driving force of grain growth in the critical deformation zone is the difference of distortion energy between two adjacent grains.In order to eliminate coarse grains after critical deformation it is proposed, on the one hand,to minimize the extent of critical deformation zone through controlled deformation;on the other hand,a short time annealing- treatment should be added shortly after fcrging in order to decrease the difference of distortion energy in the critical deformation zone. Experimental results of the above mentioned measures are satisfactory.