摘要
采用静力拉伸试验法研究了P91钢在566℃和室温时的形变强化与组织结构变化规律。结果表明,P91钢在室温条件下拉伸时自屈服至颈缩前的均匀塑性变形过程中的形变强化分3个阶段,颈缩至断裂前的局集塑性变形过程中的形变强化也分3个阶段。而在566℃时自屈服至颈缩前的均匀塑性变形过程中的形变强化为2个阶段。在局集塑性变形过程中,回火板条马氏体顺拉伸方向伸长变形的相对伸长量与颈缩量成双对数线性关系,马氏体板条束的位向朝拉伸方向转动的位向角与颈缩量也成双对数线性关系。塑性变形时位错组态出现胞状结构,随塑性变形量的增大,位错胞尺寸减小,并且顺拉伸方向伸长。形变强化能力决定了该钢在室温时的抗过载能力强。
The mechanism of strain hardening and microstructures of P91 steel at 566℃ and room temperature were studied by means of static tensile test. The results show that the strain hardening processes during uniform plastic range from yielding to necking are divided into as three stages as localized plastic range from necking to fracture at room temperature, while the deformation from yielding to necking is divided into two stages at 566℃. The relationship between the relative elongation of tempered lath martensite in tensile direction and the necking percentage is linear double logarithmic, so is the relationship between the rotating angle of martensite lath clusters to tensile direction and the necking percentage. During plastic deformation dislocation cells form and with the increase of plastic deformation, the size of dislocation cells decrease and elongate along tensile direction. The ability of strain hardening induces strong overload resistance at room temperature.
出处
《金属热处理》
CAS
CSCD
北大核心
2009年第1期28-32,共5页
Heat Treatment of Metals
基金
陕西省自然科学基金(2001C55)
关键词
P91钢
均匀塑性变形
局集塑性变形
形变强化
形变强化指数
位错胞
P91 steel
uniform plastic deformation
localized plastic deformation
strain hardening
strain hardening index
dislocation cell.
