THE EFFECT OF PLASTIC-DEFORMATION ON FRACTURE MORPHOLOGY OF THE SIGMA-PHASE IN THE NB-TI-AL SYSTEM

被引:16
作者
EBRAHIMI, F [1 ]
CASTILLOGOMEZ, JR [1 ]
机构
[1] LAGOVEN SA, CARACAS, VENEZUELA
来源
ACTA METALLURGICA ET MATERIALIA | 1992年 / 40卷 / 06期
关键词
D O I
10.1016/0956-7151(92)90442-H
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
It has been observed that in bulk specimens indentation-induced plastic deformation at room temperature causes intergranular fracture in the sigma-phase of the Nb-Ti-Al system. The TEM study of the indented regions has revealed that only intergranular microcracks, which develop when two slip bands impinge on both sides of a boundary or when a slip band arrives at a grain boundary triple point, are resulted by the dislocation-grain boundary interaction. Consequently, upon subsequent loading of the indented specimens the crack propagates intergranularly in these regions. In the undeformed sigma-phase, the accidental cracks that develop during the thin foil preparation have been found to follow a predominantly transgranular path, similar to the bulk specimen, with no dislocation activity at their tips. In contrast, in the plastically deformed regions the accidental cracks follow the path along slip bands. This phenomenon is believed to be a thin-foil effect.
引用
收藏
页码:1409 / 1416
页数:8
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