摘要
2205双相不锈钢经过固溶处理和不同程度的冷轧变形后,在950℃下保温5min,以1.5×10-3s-1的初始应变速率进行恒温超塑性拉伸试验,研究冷轧变形量对2205双相不锈钢超塑性的影响规律。观察不同冷轧程度的组织,揭示冷轧变形量影响材料超塑性的原因。试验结果表明,固溶及冷轧后的试样中,都只存在铁素体与奥氏体两相。固溶后的试样组织比较粗大,其延伸率为200%;增大冷轧变形量,铁素体和奥氏体的双相组织变得越来越细小而均匀,更易于晶粒转动,有利于超塑性变形,累积冷轧变形量从50%增加到85%时,延伸率从360%增大到1 150%,变形过程中的峰值应力从78MPa降低至约60MPa。与80%冷轧变形后的试样相比,经85%冷轧变形后的试样内部,整体出现明显的晶粒破碎现象,这种细小的组织能够起到弥散强化作用。在随后的超塑性变形过程中,作用应力较80%冷轧变形的试样高。
After solution treatment and cold rolling deformation with different reductions ,the superplastic deformation of 2205 du-lex stainless steel was tested with a initial strain rate of 1.5 ×10^-3 s^-1 after keeping 5 minutes at 950 ℃ . The effect of the cold rolling reduction on the superplasticity of 2205 duplex stainless steel was researched . The microstructures after solution treated and different reductions were observed . The relationship between the cold rolling reduction and the superplasticity was studied . The results showed that there were only ferrite and austenite in the specimens after solution treated and cold rolled .Microstructure was coarse in the specimens after solution treatment ,and its elongation was 200% . Ferrite and austenite became uniform when increased the cold rolling reduction ,and the grains became finer ,which made the grains rotation easier .And these provided favorable condition for the superplastic deformation .When the cold rolling reduction increased from 50% to 85% ,the elongation increased from 360% to 1150% ,and the peak stress decreased from 78MPa to 60MPa .Compared with the specimens with the cold rolling reduction of 80% ,the whole specimen with the reduction of 85% showed obvious broken grains ,and austenite and ferrite showed a more uniform distribution . This uniform fine microstructure had the effect of dispersion strengthening ,there-fore ,the stress of the specimen with a cold reduction of 85% was higher during the subsequent superplastic deformation process .
出处
《塑性工程学报》
CAS
CSCD
北大核心
2014年第4期97-101,共5页
Journal of Plasticity Engineering
基金
教育部高等学校科技创新工程重大项目培育资金资助项目(2010-09)
自然科学基金重点资助项目(51334006)
关键词
双相不锈钢
超塑性
冷轧变形量
峰值应力
duplex stainless steel
superplasticity
cold rolling reduction
the peak stress
