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High Temperature Material Processes: An International Quarterly of High-Technology Plasma Processes
SJR: 0.137 SNIP: 0.341 CiteScore™: 0.43

ISSN Imprimir: 1093-3611
ISSN On-line: 1940-4360

High Temperature Material Processes: An International Quarterly of High-Technology Plasma Processes

DOI: 10.1615/HighTempMatProc.2015013120
pages 37-45

AUTOGENOUS GAS TUNGSTEN ARC WELDABILITY OF FORGED TI−45AL−8.5NB−02W−02B−0.02Y ALLOY

Xiangun Xu
Materials and Chemistry School, Zhongyuan University of Technology, Zhengzhou 450007, China
Lin Song
State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China
Junpin Lin
State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China

RESUMO

The weldability of a forged Ti−45Al−8.5Nb−0.2W−0.2B−0.02Y alloy was investigated using the autogenous gas tungsten arc welding process. The results show that sound welds can be achieved for butt-joint welding of a 2.5-mm-thick sheet at a welding current of 80 A without preheating or post-welding heat treatment. Microstructure analyses show that the forged alloy exhibits an equiaxed duplex microstructure, with an average grain size of 8.5 µm, containing a 51% γ phase, 6.5% β(B2) phase, and short boride ribbons. After welding, the microstructure exhibited 300−500-µm-thick columnar dendritic structures near the fusion boundary and equiaxed dendritic structures in the majority of the weld bead. The dendritic crystals are composed of fine lamellar colonies as the major constituent and γ and β(B2) phases as the minor constituent. Long curvy borides exist in the interdendritic zones. The Vickers hardness of the fusion zone is 560−582 HV, which is higher than that of the base alloy (378 HV). This is attributed to the high volume fraction of the α2 phase in the weld. The appearance and the microstructure of the weld show that the forged Ti−45Al−8.5Nb−0.2W−0.2B−0.02Y alloy has good weldability.