Effects of surface mechanical attrition treatment (SMAT) on a rough surface of AISI 316L stainless steel
Effects of surface mechanical attrition treatment (SMAT) on a rough surface of AISI 316L stainless steel
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DOI：
10.1016/j.apsusc.2012.01.021
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发表时间：
2012-03
影响因子：
6.7
通讯作者：
B. Arifvianto;Suyitno;M. Mahardika
中科院分区：
文献类型：
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作者：
B. Arifvianto;Suyitno;M. Mahardika
表面机械研磨处理（SMAT）通过在金属材料表面形成纳米晶来提高其力学性能。它还修改了工作表面的形态和粗糙度。表面粗糙化的SMAT已被报道以前在一个光滑的标本，但在这项研究中的起点是一个粗糙的表面，并观察到一个平滑的现象。本文阐述了SMAT过程中AISI 316L不锈钢表面光滑化的机理。对粗糙度Ra=3.98μm的试样进行SMAT，时间为0- 20 min。SMAT中使用的研磨球的尺寸从3.18 mm变化到6.35 mm。研究了SMAT对试样亚表面显微硬度、表面形貌、粗糙度和质量减少的影响。结果表明，SMAT使钢的表面和亚表面的显微硬度增加。研磨球的冲击使表面变形并在该层处产生平坦状结构。表面粗糙度减小，直到在SMAT中达到饱和。试样的质量减少也被检测到，并且可以指示SMAT的材料去除或表面侵蚀。磨球的尺寸被认为是决定SMAT过程中的粗糙度演变和材料去除模式的重要特征。从这项研究中，两个主要的机制，在SMAT过程中的表面形貌和粗糙度的演变提出，即压痕和表面侵蚀的磨球的多次冲击。与以往实验结果的对比研究表明，初始表面粗糙度对SMAT加工硬化没有影响，但对饱和粗糙度值略有影响。
Surface mechanical attrition treatment (SMAT) improves mechanical properties of metallic materials through the formation of nanocrystallites at their surface layer. It also modifies the morphology and roughness of the work surface. Surface roughening by the SMAT has been reported previously in a smooth specimen, however in this study the starting point was a rough surface and a smoothening phenomenon is observed. In this paper, the mechanisms involved in the surface smoothening of AISI 316L stainless steel during the SMAT are elucidated. The SMAT was conducted on a specimen with a roughness of Ra=3.98μm for 0–20min. The size of milling balls used in the SMAT was varied from 3.18mm to 6.35mm. The modification of subsurface microhardness, surface morphology, roughness and mass reduction of the specimen due to the SMAT were studied. The result shows the increasing microhardness of the surface and subsurface of the steel due to the SMAT. The impacts of milling balls deform the surface and produce a flat-like structure at this layer. Surface roughness decreases until its saturation is achieved in the SMAT. The mass reduction of the specimens is also detected and may indicate material removal or surface erosion by the SMAT. The size of milling ball is found to be the important feature determining the pattern of roughness evolution and material removal during the SMAT. From this study, two principal mechanisms in the evolution of surface morphology and roughness during the SMAT are proposed, i.e. indentation and surface erosion by the multiple impacts of milling balls. A comparative study with the results of the previous experiment indicates that the initial surface roughness has no influence in the work hardening by the SMAT but it does slightly on the saturated roughness value obtained by this treatment.