Recent development of the SMAT and mechanical behavior of steels
This presentation will summarize the recent work related to a kind of new nanomaterials produced by the surface mechanical attrition treatment (SMAT).The concept of surface nanocrystallization of metallic materials will be presented1.In terms of the grain refinement mechanism induced by plastic deformation,a novel surface mechanical attrition (SMA)technique was developed for synthesizing a nanostructured surface layer on metallic materials in order to upgrade the overall properties and performance.The different process of SMA technique and the nanostructure of the SMA-treated surface layer will be described.The grain refinement mechanism of the surface layer during the SMA treatment will be analyzed in terms of the nanostructure observations in several typical materials (Al,Fe,Stainless steel,Ni,Ti,Co,Cu,Zr etc.)2-9.The nanostructured layer with a grain size of 10 nm to 15 nm was generated on the surface of material up to a depth of 50μm.Significant enhancements in mechanical properties of the nanostructured surface layer in different materials will be analyzed10-12.The evidence obtained so far has already indicated that a nanostructured surface layer synthesized by means of SMAT on metallic materials provides many unique opportunities in terms of both basic scientific research and technological applications.Very high yield stress (5 times of the base material)on the surface layer of the material obtained by the SMAT has been observed in stainless steel 316L13.So many industrial applications including the development of high performance materials for MEMS applications using the nanostructured surface layer (10 μm to 50 μm)as a base material for small size components can be anticipated.The developed materials are also porosity free materials which can be used as reference material for the local mechanical behavior investigation technique such as the nanoindentation14-20.The role of residual stress induced during the treatment will be investigated and discussed21.The SMAT can increase drastically the diffusion properties of materials and some examples of the enhancement of the surface properties will be shown.The first results show that the SMAT is a new efficient process for increasing the wear and corrosion behavior of the materials using the hybrid treatment22-25.The effect of surface nanostructures on the mechanical behavior and on the failure mechanism of metallic material shows the possibility to develop a new strength gradient composite.A concept for the design and the realization of structural nanomaterials with high yield strength and high ductility through a combination of the SMAT and co-rolling technique will be presented26-27.The new approaches of the experimental and computational mechanics of nanostructured for the investigation of this class of materials will be also presented28.
Lu Jian
Department of Mechanical Engineering,The Hong Kong Polytechnic University,Hung Horn Kowloon,Hong Kong
国际会议
上海
英文
895-896
2008-09-26（万方平台首次上网日期，不代表论文的发表时间）