SIZE EFFECT OF FLOW STRESS EN ISOTHERMAL UPSETTING DEFORMATION

摘要：

With the miniaturization of parts, size effect occurs. The isothermal forming processes are performed to obtain homogenizing deformation. In the paper, a serial of isothermal upsetting tests are carried out with billets of different dimensions. Difference of flow stress is accepted as the parameter to evaluate the size dependence of flow stress on billets dimensions. The experimental results show that size effect occurs clearly. With the increasing of temperature, the difference of flow stress becomes smaller, which means that the degree of size dependence is reduced. Scatter of flow stress is observed in the tests at room temperature. When the deformation temperature is raised, the fluctuation of flow stress tends towards decreasing. In order to investigate the effect of grain size, different grain size is obtained with the heat treatment process. At the same temperature, the difference of flow stress increases with the increasing of grain size. These phenomena can be explained from the viewpoint of polycrystalline structure of material. The anisotropy of individual grain is appeared obviously, which leads the fluctuation of flow stress. In the isothermal deformation, the effect of single grain is smaller than that at room temperature.

关键词： Micro-forming isothermal upsetting size effect scatter of flow stress

作者: BIN GUO CHUNJU WANG DEBIN SHAN LINING SUN

作者单位: School of Materials Science and Engineering, Harbin Institute of Technology, 92 West Dazhi Street, H Robot Institute of Technology, Harbin Institute of Technology, 92 West Dazhi Street, Harbin, Heilong

会议类型: 国际会议

会议名称: 第五届先进材料与加工国际会议(Fifth International Conference on Advanced Materials and Processing ICAMP-5)

会议地点: 哈尔滨

会议语种:英文

页码: 1745-1750

在线出版日期: 2008-09-03（万方平台首次上网日期，不代表论文的发表时间）