中國有色金屬學(xué)報(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 23 No. 3 March 2013 |
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. The 23rd Research Institute, The Second Academy of China Aerospace, Beijing 100024, China）
Abstract:The oxide distribution and microstructure in longitudinal and transverse welding zones during the billet-to-billet extrusion process through porthole die were adequately investigated by means of finite element method, scanning electron microscopy and optical microscopy. The results indicate that the oxides exist at the interface between the matrix and transverse welding zone rather than longitudinal welding seam. The longitudinal welding zone reveals a darker band including the largest grain with irregular shape due to the abnormal grain growth under the heavy shear deformation and high temperature. The transverse welding zone consists of equiaxed recrystallized grains which are a little finer than those in the longitudinal welding seam.
Key words: porthole die; extrusion welding; oxide distribution; welding microstructure
