Effects of Laser Welding and Post-Weld Heat Treatment on Microstructure and Mechanical Properties of Aged Ti55531 Alloy
| Autor: | Linjie Zhang, Shang Xiangtao, Jun-Yu Pei, Jun Wu, Jian Long, Xie Miaoxia |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Heat-affected zone
post-weld heat treatment Materials science Weldability microstructure 02 engineering and technology Welding mechanical properties 01 natural sciences lcsh:Technology Article law.invention law Phase (matter) 0103 physical sciences Ultimate tensile strength General Materials Science Lamellar structure Composite material lcsh:Microscopy lcsh:QC120-168.85 010302 applied physics lcsh:QH201-278.5 lcsh:T Laser beam welding 021001 nanoscience & nanotechnology lcsh:TA1-2040 laser welding Grain boundary lcsh:Descriptive and experimental mechanics Ti-5Al-5Mo-5V-3Cr-1Zr lcsh:Electrical engineering. Electronics. Nuclear engineering 0210 nano-technology lcsh:Engineering (General). Civil engineering (General) lcsh:TK1-9971 |
| Zdroj: | Materials Volume 11 Issue 10 Materials, Vol 11, Iss 10, p 1907 (2018) |
| ISSN: | 1996-1944 |
| Popis: | As one of the relatively new titanium (Ti) alloys in the engineering field, &beta Ti alloy&ndash Ti55531 has attracted a great deal of attention due to its excellent mechanical properties, while a few research papers on weldability and the post-weld heat treatment (PWHT) process of Ti55531 have been reported. Based on an orthogonal experiment design, the parameters of laser beam welding (LBW) of Ti55531 alloy with a thickness of 2 mm were optimized. Moreover, the influences of welding parameters and PWHT on the microstructures and performance of the laser-welded joint of Ti55531 were analyzed. The results showed that, for microstructures in different zones of as-welded joints of Ti55531: three forms of &alpha phases (i.e., equiaxial &alpha p phase, lamellar &alpha S phase, and &alpha GB phase at grain boundaries) were observed in base metal (BM) in the heat affected zone (HAZ), part of lamellar &alpha S phase had dissolved while equiaxial &alpha p phase had grown the fusion zone (FZ) mainly consisted of &beta phase, which presented as coarse columnar crystals. After the PWHT process, the microstructures of the welded joint were changed: in the BM zone, &alpha phase at grain boundary disappeared and lamellar &alpha phase decreased in the HAZ, the edge of &alpha p phase obviously dissolved in the FZ, plenty of compact needle-like &alpha phases were observed. The tensile strength of the as-welded joint was about 940 MPa and then increased to 1161 MPa after PWHT, which were 78.4% and 96.8% of that of the original BM respectively. The fracture position transformed from the interface between the FZ and HAZ to the BM during tensile tests after PWHT. |
| Databáze: | OpenAIRE |
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