摘要
采用真空等温热变形试验机在恒应变速率和真空环境条件下,对挤压态镍基粉末高温合金试样20 mm×20mm×50 mm进行了等温应变梯度变形试验研究。分别在最大应变速率0.001、0.01、0.1、1 s-1和变形温度1070℃条件下,所有试样最大应变处等温变形至真应变1.0。结果表明:随应变速率的升高,异常晶粒长大位置由大应变区逐渐移至小应变区,异常晶粒长大变得严重,而在高应变速率时,温升越大,试样异常晶粒长大的情况越严重;借助EBSD技术可以计算晶粒形变程度,大应变区域具有较大的晶粒形变程度,异常晶粒长大区域具有较小的晶粒形变程度,由于晶粒形变程度高的区域位错密度大,晶内储存能量较高,易于发生再结晶,晶粒形变程度低的区域位错密度小,位错优先用于晶粒长大。
The isothermal strain gradient deformation test of the 20 mm ×20 mm ×50 mm extruded nickel-based power metallurgy superalloy samples was carried out by using the vacuum isothermal deformation tester at constant strain rate under the vacuum environment. All the samples at the maximum strain place were deformed to true strain 1.0 at isothermy of 1070℃with the maximum strain rates of 0.001, 0.01, 0.1, 1 s-1respectively. The results show that with the increase of strain rate, the abnormal grain growth position gradually moves from large strain zone to small strain zone and the abnormal grain growth becomes more severe. While at high strain rate,the greater the temperature rises, more serious cases of sample the abnormal grain growth appears. The degree of grain deformation can be calculated by EBSD, large strain zone has larger degree of grain deformation, and the abnormal grain growth zone has smaller degree of grain deformation. As dislocation density in the region of high grain deformation degree is big, and the stored energy in the crystal is higher, it is easy to cause recrystallization;as dislocation density in the region of high grain deformation degree is small, the dislocations are priority for grain growth.
出处
《热加工工艺》
CSCD
北大核心
2015年第13期42-45,49,共5页
Hot Working Technology
关键词
应变速率
镍基粉末高温合金
异常晶粒长大
strain rate
Ni-based power metallurgy superalloy
abnormal grain growth
作者简介
宋晓俊（1983-），男，河南信阳人，硕士，主要研究方向：高温合金成形工艺；电话：18701117751；E—mail：songxiaojun25@126．com
