tailieunhanh - Fatigue crack growth at the representative zones in friction stir welding of a heat treatable aluminium alloy at 200oC

Although the grain microstructure of the TMAZ was significantly refined in comparison with that of BM, the FCG rate in TMAZ and base metal was shifted a comparable amount when the test temperature was elevated from room temperature to 200 oC. In the metallurgical view, the FCG rate in the fine grain TMAZ was higher than that in coarse grain HAZ and base metal site. | Vietnam Journal of Science and Technology 56 (1) (2018) 39-46 DOI: FATIGUE CRACK GROWTH AT THE REPRESENTATIVE ZONES IN FRICTION STIR WELDING OF A HEAT-TREATABLE ALUMINIUM ALLOY AT 200 oC Tran Hung Tra Nha Trang University, 2 Nguyen Dinh Chieu, Nha Trang, Viet Nam Email: tra@ Received: 16 June 2017; Accepted for publication: 6 November 2017 Abstract. Aluminium alloy 6063-T5 plates were joined by friction stir welding technique. The fatigue crack growth (FCG) in the thermo-mechanical affected zone (TMAZ) and in the heat affected zone (HAZ) of the welding was examined at 200 oC. Although the grain microstructure of the TMAZ was significantly refined in comparison with that of BM, the FCG rate in TMAZ and base metal was shifted a comparable amount when the test temperature was elevated from room temperature to 200 oC. In the metallurgical view, the FCG rate in the fine grain TMAZ was higher than that in coarse grain HAZ and base metal site. Keywords: aluminum alloy 6063-T5, friction stir welding, fatigue crack growth, HAZ, TMAZ, high temperature. Classification numbers: ; . 1. INTRODUCTION Aluminium alloys are one of the key materials possessing several advantages such as light weight, relatively low cost, heat treatable, high specific strength. Thus these alloys have been applied in the wide range of applications, especially in the aviation field [1]. However, one of the most challenges in using these alloys associates with their welding. Friction stir welding (FSW) is emerging as a preeminent technology for solving this obstacle. This FSW is suitable for joining light weight alloys such as aluminium alloys for both similar and dissimilar welding [2,3]. Furthermore, this FSW is recognized as a green technique in metal joining with high energy efficiency and versatility. This welding technique has been found to be a key joining technology in the near future. Since the welding can be obtained at the temperature below .