摘要
工业纯Ａｌ在５．０ｓ－１的恒表面应变速率条件下，４００℃及以下温度变形时，仅发生动态回复，形成近似等轴亚晶组织；４５０℃以上变形时，主要软化机制为动态再结晶，大变形后，形成与原始粗晶组织不同的细小均匀的动态再结晶晶粒．高温扭转时的等效应力－应变曲线呈现周期性锯齿流变特征．线性回归结果表明，回复亚晶尺寸和Ｚｅｎｅｒ－Ｈｏｌｌｏｍｏｎ参数间满足Ｈａｌｌ－Ｐｅｔｃｈ关系．
Hot torsion testing was conducted on commercial aluminium at 300-500℃ and constant surface strain rate of 5.0 s-1 to study the dynamic recovery and dynamic recrystallization. The microstructural observations under OM and TEM show that the dynamic recovery is the only operative restoration mechanism if the deformation temperatures are below 400℃, and substructure consists of approximately equiaxial subgrains.The material, however, is mainly softened by dynamic recrystallization when torsion temperatures exceed 450℃ . The fine and homogeneous recrystallized grains, which are different from the coarse initial grains, develops over the gauge length of the specimens after large strain of about 3.85.The essential features of the torsional equivalent stress-strain behaviours are consistent with that of periodically oscillating flow. A Hall-Petch relationship was satisfied by linear regression between the reciprocal of average diameter of subgrains and Zener-Hollomon parameters.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
1995年第9期A411-A416,共6页
Acta Metallurgica Sinica
关键词
扭转
动态
回复
再结晶
铝
纯铝
晶粒
高温
应变
aluminium, torsion, dynamic recovery, dynamic recrystallization.
