摘要
研究了铸态690合金在不同初始组织条件下(细柱状晶、粗柱状晶和等轴枝晶)的热压缩流变曲线和变形组织,并对变形后样品的微取向进行了分析,结果表明:在铸态条件下,690合金的高温流变抗力随着变形温度降低、应变速率升高和变形量增大而升高,在50%的压缩量下,高温(1200℃)和高速(1 s^(-1))有利于动态再结晶的发生。当压缩方向垂直于柱状晶方向时,二次枝晶滑动作为一种变形机制,导致应变速率敏感因子增大,此时细柱状晶样品变形抗力最小,再结晶比例最低,而初始组织为粗柱状晶和等轴枝晶的样品分别具有最大的变形抗力和最有利的动态再结晶条件。
Hot compression flow curves and microstructure of alloy 690 samples with different initial microstructure（ i. e. fine columnar grains,coarse columnar grains and equiaxed dendrites） were studied. Micro-orientations were also analyzed after deformation. The results indicate that flow stresses can increase with the reduction of temperature and the increasing of strain rate and true strain for 690 cast ingot.High temperature（ 1200 ℃） and strain rate（ 1 s^-1） are in favor of dynamic recrystallization（ DRX） at strain of 50%. Secondary dendrite sliding is an effective deformation mechanism when the compression direction is perpendicular to columnar grains,leading to the increase of strain rate sensitivity. On this premise,samples with fine columnar grains can get the lowest flow stress and recrystallization fraction. In contrast,coarse grain and equiaxed dendrite specimens have the largest stress and most favorable for DRX kinetics,respectively.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2015年第12期44-49,共6页
Transactions of Materials and Heat Treatment
基金
国家自然科学基金青年科学基金(51301085)
南京工程学院引进人才科研启动基金(YKJ201305)
关键词
柱状晶
枝晶滑动
动态再结晶
690合金
columnar grain
dendrite sliding
dynamic recrystallization
690 alloy
