A microstructural investigation of the surface of a drilled hole in carbon steels
A microstructural investigation of the surface of a drilled hole in carbon steels
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DOI：
10.1016/j.actamat.2006.09.043
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发表时间：
2007-02-01
期刊：
影响因子：
9.4
通讯作者：
Tsuchiya, K.
中科院分区：
文献类型：
--
作者：
Li, J. G.;Umemoto, M.;Tsuchiya, K.
研究了碳钢在不同钻削条件下形成的孔表面的显微组织。结果表明，钻削工艺参数和基体硬度对表面组织有很大的影响。白色腐蚀层由平均晶粒尺寸为几十nm的等轴纳米晶结构层和沿深度方向含有新鲜马氏体沿着的亚微米晶粒层组成，在具有高基体硬度的碳钢中以中等至高的切削速度钻削时在孔表面上形成。孔表面高含量奥氏体的存在表明，在高速钻削过程中体心立方和面心立方相发生了动态相变。研究表明，钻孔表面的超细结构层是在大应变梯度和高应变速率条件下，由剧烈塑性变形引起的DPT产生的。(c)2006 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
The microstructure of the surface of drilled holes generated under different drilling conditions in carbon steels has been investigated. It is found that the surface microstructure depends strongly on the drilling parameters and the hardness of the matrix. White etching layers, composed of an equiaxed nanocrystalline structure layer with an average grain size of the order of several 10 nm and a submicron grained layer containing fresh martensite along the depth, formed on the hole surfaces during drilling at moderate to high cutting speed in carbon steels with high matrix hardness. The existence of a high content of austenite at the hole surface suggests that dynamic phase transformation (DPT) from body-centered cubic to face-centered cubic occurred during high-speed drilling. It is proposed that the ultrafine structure layer on the surface of a drilled hole is produced by severe plastic deformation-induced DPT together with a large strain gradient and high strain rate. (c) 2006 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.