INVESTIGATION OF FATIGUE MECHANICAL PROPERTIES OF A POLYCRYSTALLINE SOLID AT MESOSCOPIC SCALE USING DEPTH-SENSING INDENTATION (DSI) TECHNIQUE

摘要：

A series of experiments including constant amplitude low-cycle fatigue tests,depth-sensing indentation (DSI) measurements and transmission electron microscopy (TEM) observations were performed to obtain the changecharacteristics of fatigue mesoscopic mechanical properties of SUS304-HP austenitic stainless steel as well as their micromechanisms.The basic mechanical properties,such as the indentation hardness ( H ),Youngs modulus (E),yield strength (σys),strain hardening exponent (n) and plastic energy ( Wp),of the cyclically deformed material at mesoscopic scale were extracted from the measured indentation load-depth (P-h ) curves.It is shown that for the polycrystalline metal investigated the cyclic plastic deformation remarkably influences its subsequent elastic-plastic response of the small volume material to the indentation process.As the strain amplitudes increases,the mesoscopic mechanical properties (H,E,σys,and n) show increase,while the plastic energy of the indentation (W p) exhibits a decrease process.Microstructure observations using TEM reveal that with increasing strain amplitudes the dislocation substructures in the material tend towards cell formation and the size of dislocation cells tend to progressively decrease.The dependence of the microstructures on the applied strain amplitude is thus responsible for the change characteristics of the mesoscopic mechanical properties.

关键词： DSI technique fatigue mechanical properties mesoscopic scale

作者: D.Y.Ye M.Y.Li H.B.Cha

作者单位: Institute for Chemical Mechanical Engineering,Zhejiang University,Hangzhou,Zhejiang 310027,China

会议类型: 国际会议

会议名称: 第二届国际非均质材料力学会议(The Second International Conference on Heterogeneous Material Mechanics)

会议地点: 安徽黄山

会议语种:英文

页码: 285

在线出版日期: 2008-06-03（万方平台首次上网日期，不代表论文的发表时间）