摘要
对取自同一块晶体的铜三晶（Ｔｃ）和双晶（ＢＣ）试样进行了恒塑性应变幅控制对称拉压疲劳实验，轴向塑性应变幅范围１．０×１０(－４)≤ ≤ ４×１０(－３)。结果表明，在低应变幅下，三晶及双晶试样的初始循环硬化曲线几乎重合。在较高应变幅下，三晶试样的硬化曲线高于双晶试样的硬化曲线且随着应变幅的增加差距增大。三晶体的循环应力应变（ＣＳＳ）曲线明显高于双晶的ＣＳＳ曲线。不论对ＴＣ还是ＢＣ试样，当 １＜１．５×１０(－３)时，轴向饱和应力随着的增加而缓慢上升，而当＞１．５×１０(－３)时，轴向饱和应力则随着Ｅｐｌ的增加快速上升。两曲线都无明显的平台区出现．表面形貌观察表明，在低应变幅下，三晶交点（ＴＪ）对各晶粒的主滑移有阻碍作用，在高应变幅下，在三晶交点附近，由于各晶粒的应变不相容性而产生的内应力导致了多滑移系统的启动．上述力学结果同表面形貌观察相一致。另外，在＞７．０×１０(－４)情况下。
Cyclic deformation was applied to a copper tricrystal (TC) as well as a bicrystal (BC)at constant plastic axial strain amplitude in the range of 1.0-× 10-4 < < 4 × 10-3. The initial cyclichardening of TC was found to be similar to that of BC at low strain amplitudes. The cyclic hardening ofTC is higher than that of BC at higher and the distinction becomes pronounced with increasing.The cyclic stress-strain (CSS) curve of TC is obviously higher than that of BC. No matter for TC and BCspecimens, as increases slowly with increasing pl when pl < 1 .5 × 10-3， of TC and BC increases obviouslyafter 1.5× 10-3. Both curves show almost no plateau. Two effects of the grain boundary triple junction(TJ) on slip have been found: one is retardation to the primary slip at lower strain amplitudes, the otheris the activation of multiple slip systems due to the internal stresses caused by the strain incompatibilities.The above mechanical behaviors are in accord with surface morphologies. Microcracks nucleated near TJfor pl greater than 7.0× 10-4.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
1999年第2期211-216,共6页
Acta Metallurgica Sinica
基金
国家自然科学基金!59671035
关键词
循环形变
铜三晶体
铜双晶体
滑移形貌
cyclic deformation, copper tricrystal, copper bicrystal, slip morphology
