GRAIN-BOUNDARY CAVITATION UNDER VARIOUS STATES OF APPLIED STRESS
GRAIN-BOUNDARY CAVITATION UNDER VARIOUS STATES OF APPLIED STRESS
复制标题
DOI：
10.1098/rspa.1976.0071
复制
发表时间：
1976-01-01
影响因子：
--
通讯作者：
RODGERS, MJ
中科院分区：
文献类型：
--
作者：
DYSON, BF;LOVEDAY, MS;RODGERS, MJ
当在三种不同应力状态中的任何一种下塑性变形后进行短暂退火时，在Nimonic 80A中产生亚微米晶界空腔。拉伸、扭转和压缩试样以系统的方式进行塑性应变，然后在750 °C下退火2小时。详细的定量观察与1 MV显微镜表明，每单位体积的空腔的数量是一个函数的剪切应变和独立的应力状态。此外，测量还揭示了一个令人惊讶的结果，即大多数空洞位于平行于最大主应力轴的晶界上。然而，在随后的拉伸蠕变过程中发生优先空穴生长，这些平行边界上的空穴要么保持不变的大小或减少，而那些垂直于所施加的应力轴的边界上的空穴生长相对较快，从而产生通常的空洞拉伸样品的外观。当塑性变形和蠕变之间的扭矩方向相反时，塑性应变对扭转蠕变塑性更不利，这与各向异性空泡边界分布相一致。结果与空洞是由晶粒内部滑移产生并由塑性变形引起的内部拉应力稳定的假设是一致的。
Submicrometre grain boundary cavities are produced in Nimonic 80A when plastic deformation in any of three different stress states is followed by a short anneal. Tension, torsion and compression specimens were plastically strained in a systematic manner and then annealed for 2 h at 750 °C. Detailed quantitative observations with a 1 MV microscope showed that the number of cavities per unit volume was a function of the shear strain and independent of the stress state. Furthermore the measurements revealed the surprising result that most cavities were on those grain boundaries which were parallel to the maximum principal stress axis. However, Preferential cavity growth occurred during subsequent tensile creep and cavities on these parallel boundaries either remained constant in size or diminished while those on boundaries which were orthogonal to the applied stress axis grew relatively quickly, thus producing the usual appearance of cavitated tensile samples. Plastic strain was more detrimental to torsional creep ductility when the direction of torque between plastic deformation and creep was reversed which is in accordance with the anisotropic cavitated boundary distribution. The results are compatible with the hypothesis that cavities are produced by grain interior slip and stabilized by plastic deformation induced internal tensile stresses.