J. Mater. Sci. Technol. ›› 2014, Vol. 30 ›› Issue (12): 1251-1254.DOI: 10.1016/j.jmst.2014.07.017

• Orginal Article • Previous Articles     Next Articles

Improving Corrosion Resistance of Friction Stir Welding Joint of 7075 Aluminum Alloy by Micro-arc Oxidation

Yue Yang, Leilei Zhou   

  1. Key Laboratory of Advanced Structural Materials, Ministry of Education, Changchun University of Technology, Changchun 130012, China
  • Revised:2014-01-20 Online:2014-12-20 Published:2015-07-23
  • Supported by:
    This work was supported by the Program for New Century Excellent Talents from the Ministry of Education (Grant No. NCET-11-0984).

Abstract: Hot ductility, stress-strain behavior and high temperature tensile fracture behavior of wrought 316LN stainless steel were investigated. Hot tensile tests were carried out on a Gleeble 1500D thermal simulator system at a strain rate of 0.5 s-1 over the temperature range 650-1300℃. The percentage reduction of area (RA) decreased with the increasing deformation temperature over the range of 650-850℃, and then starting from 850℃, it began to increase dramatically with values over 85% above 1000℃. When the deformation temperature comes to 1300℃, RA decreased sharply as a result of the grain coarsening due to over-heating. With the help of optical microscopy, dynamic recrystallization (DRX) was observed for the steel deformed at temperature over 1000℃. The enhancement of ductility induced by DRX was considered to play an important role in inhibition of the crack propagation. The high temperature tensile failure process of 316LN includes the nucleation, growth, and aggregation of microscopic cavities. The SEM/EDS results show that the sulfide and alumina at grain boundaries may be responsible to the formation process of cracks.

Key words: Aluminum alloy, Micro-arc oxidation, Friction stir welding joint, Corrosion resistance