摘要
采用喷射成形技术制备一种新型镍基高温合金,并对其进行热等静压处理。在Gleeble-3500热力模拟试验机上进行热压缩试验,利用光学显微镜、扫描电镜(SEM)以及透射电镜(TEM)等方法对其变形机制进行研究。结果表明,高应变速率(10s-1)下变形,摩擦产生的热量使试样的实际变形温度高于名义变形温度,促进了动态再结晶组织的形成;高应变速率下形成的孪晶可进一步激发滑移变形,而亚晶内形成的大量位错对变形起到协调作用,保证了变形顺利进行;建立了再结晶晶粒尺寸模型lnd=8.26-0.058lnZ,表明随应变速率的增加,晶粒尺寸减小,合金变形能力增加,这与实验结果相一致。
A new nickel base superalloy was prepared by spray forming process,which was then treated by hot-isostatic pressing. The hot compression tests were conducted under various testing conditions by a Gleeble-3500 thermal simulation instrument. The deformation mechanisms were studied by optical microscope,scanning electron microscope （SEM）,and transmission electron microscope （TEM）. The results show that the actual deformation temperature is higher than the nominal deformation temperature at the high strain rate of 10 s^-1 due to the friction heating and thus the dynamic recrystallization （DRX） is promoted. The twin grain formed at the high strain rate can further excite sliding deformation,while lots of dislocation formed in subgrains can coordinate the deformation to ensure its proceeding. The model of the DRX grain size is established as lnd=8.26–0.058lnZ. It shows that at the fixed testing temperature,with the increase of Z parameter,viz. the increase of strain rate,the DRX grain is refined and the deformability is enhanced,which is consistent with the testing results.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2010年第7期1210-1214,共5页
Rare Metal Materials and Engineering
基金
黑龙江省教育厅项目(10051050)
哈尔滨市青年基金(2004AFQXJ039)
关键词
喷射成形高温合金
动态再结晶
应变速率
位错
孪晶
spray formed superalloy
dynamic recrystallization
strain rate
dislocation
twin grain
