The effect of TLP bonding temperature on microstructural and mechanical property of joints made using FSX-414 superalloy

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• 作者：R. Bakhtiari^a ; ^b ; ¹ ; ^{r_bakhtiari@mehr.sharif.edu} ; ^{bakhtiari.r@gmail.com} ; A. Ekrami^a ; ^{ekrami@sharif.ir} ; T.I. Khan^b ; ^{tkhan@ucalgary.ca}
• 关键词：Mechanical characterization ; Microanalysis ; Electron microscopy ; Superalloys ; Bonding ; Phase transformation
• 刊名：Materials Science and Engineering ; A
• 出版年：2012
• 期刊代码：61_09215093
• 类别：ms
• 出版时间：1 June, 2012
• 卷：546
• 期：Complete
• 页码：291-300
• 文件大小：2644 K

摘要

The bonding temperature is an important parameter for optimization of the Transient Liquid Phase (TLP) bonding process in order to achieve a sound joint with good mechanical properties. However, the bonding temperature used can also be restricted by the microstructural stability of the base metal. In this study, the effect of bonding temperature (1050-1200 掳C) on the joint microstructure and mechanical properties was studied for TLP bonding of FSX-414 superalloy using MBF-80 interlayer with thickness of 50 渭m.

Increasing bonding temperature from 1050 to 1150 掳C caused reduction in the time required for complete isothermal solidification in agreement with models based on the diffusion induced solid/liquid interface motion. But even after 120 min hold time at 1200 掳C, isothermal solidification was not complete and significant liquid penetration at grain boundaries adjacent to the joints was observed. Heating the base metal specimens to various temperatures of 1160-1190 掳C and then water quenching, showed that 1190 掳C is the critical temperature for base metal liquefaction.

The maximum hardness at isothermal solidification zone and maximum hardness of phases at joint and diffusion affected zone was increased and decreased, respectively, with increasing temperature up to 1150 掳C. Also, the shear strength at complete isothermal solidification was increased at the same trend. But a significant reduction in shear strength and maximum ISZ hardness were observed for sample bonded at 1200 掳C. Separated bond-line and fracture surface and also cleavage-like features were seen at fracture surface of shear tested samples for this temperature which are evidences of brittle fracture.