کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1579121 | 1514824 | 2010 | 7 صفحه PDF | دانلود رایگان |
We report our investigation of the block boundary and sub-block boundary strengths of lath martensite evaluated through a micro-bending test. The sub-block boundaries contribute very little to the macroscopic strength of the lath martensite. In contrast, the presence of a block boundary in the specimen greatly increased the strength. In addition, the block boundary induced a serrated flow and load drop after yielding in the load–displacement curve. The load drop and serrated flow were attributable to dislocation pile-up and subsequent propagation of dislocations across the block boundary. In a microstructural observation of specimens after deformation, we found that a block boundary significantly restricts the motion of dislocations, while a sub-block boundary does not. We concluded that the block boundary is the most effective grain boundary for strength in lath martensite.
Research highlights▶ The sub-block boundaries contribute very little to the macroscopic strength of lath martensite. ▶ The presence of a block boundary greatly increased the strength of lath martensite. ▶ The block boundary induced a serrated flow and load drop after yielding in the load–displacement curve. ▶ The block boundary is the most effective grain boundary for strength in lath martensite.
Journal: Materials Science and Engineering: A - Volume 527, Issues 29–30, 15 November 2010, Pages 7538–7544