Sliding wear behavior of sub-microcrystalline pure iron produced by high-pressure torsion straining
Sliding wear behavior of sub-microcrystalline pure iron produced by high-pressure torsion straining
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DOI：
10.1016/j.wear.2015.04.014
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发表时间：
2015-08-15
期刊：
影响因子：
5
通讯作者：
Sentoku, Eisuke
中科院分区：
文献类型：
--
作者：
Kato, Hirotaka;Todaka, Yoshikazu;Sentoku, Eisuke
采用球-盘结构研究了亚微晶纯铁高压扭转（HPT）变形圆盘的滑动磨损行为，考察了HPT变形过程中应变和磨损时间的影响。结果表明，在HPT过程中，磨损量随着转动次数的增加而减小，初始阶段的比磨损率与盘的维氏硬度成反比。然而，对于长时间的磨损试验时间，磨损率变得非常小的非变形和HPT处理的标本，因为从粘着剪切磨损过渡到滑动过程中所造成的（i）晶粒细化在磨损诱导层，（ii）亚微米磨损颗粒粘附到磨损表面，和（iii）表面平整的局部粗糙变形。磨损试验后，未变形和HPT处理的试样之间磨损表面下的显微组织和硬度没有显着差异。因此，HPT仅在早期阶段改善耐磨性，并且对于长期磨损试验变得不太有效。这项研究是第一次表明，由HPT应变产生的亚微米晶粒通过摩擦剪切应变进一步细化到100-150 nm的尺寸，而铁的晶粒细化在HPT加工中进一步应变时达到饱和。(C)2015 Elsevier B. V.版权所有。
Sliding wear behavior of sub-microcrystalline pure iron disks produced by high-pressure torsion (HPT) straining was studied using a ball-on-disk configuration, and the effects of the strain in the HPT process and of the duration of wear tests were investigated. It was found that the wear amount decreased with increasing number of turns during HPT, and that the specific wear rate of the initial stage was inversely proportional to the Vickers hardness of the disks. However, for long wear test times, the wear rate became very small for both non-deformed and HPT-processed specimens, because of transition from adhesive shearing wear to sliding process which was caused by (i) grain refinement at the wear-induced layer, (ii) submicron wear particles adhered to the worn surface, and (iii) surface flattening by local asperity deformation. There was no significant difference in microstructure and hardness beneath the worn surface between non-deformed and HPT-processed specimens after the wear tests. Thus HPT improved the wear resistance only at the early stage, and became less effective for long wear tests. This study is the first to show that submicron grains produced by HPT straining were further refined to a size of 100-150 nm by friction shear straining while grain refinement of iron is saturated upon further straining in HPT processing. (C) 2015 Elsevier B.V. All rights reserved.