Effect of La addition on high-temperature order-disorder phase transformation in Fe − 18Ga alloy. (August 2019)

• Record Type: Journal Article
• Authors: Sun, Meng; Wu, Yinxing; Jiang, Weibin; Liu, Wang; Wang, Xianping; Gao, Yunxia; Liu, Rui; Hao, Ting; Wen, Wen; Fang, Qianfeng
• Is Part Of: Intermetallics. Volume 111(2019:Aug.)
• Publication Date: 2019-08
• Subjects: Internal friction -- Order-disorder -- LaGa2 -- Zener relaxation -- Hardness; Intermetallic compounds -- Metallography -- Periodicals; Metallic glasses -- Periodicals; Composés intermétalliques -- Métallographie -- Périodiques; 669.94
• DOI: 10.1016/j.intermet.2019.106496
• Languages: English
• ISSNs: 0966-9795

Abstract

Abstract: The microstructure, internal friction (IF) behavior spectra, heat flow curves, and mechanical strength of Fe-18Ga- x La ( x = 0.05, 0.1, 0.2, 0.5, and 1.0 at.%) alloys were systematically analyzed in this investigation. In the IF spectra, a relaxation IF peak (Labeled as P 1 ) and a peak related to order-disorder phase transition (Labeled as P tr ) are observed in the temperature range of 400 °C–690 °C. It is found trace La doping has a significant effect on the P tr peak. With the increase of the La-doped content, the peak of P tr gradually shifts to a lower temperature and the net peak height decreases. Combining with phase diagram, DSC, Grazing Incidence X-ray diffraction (GI-XRD) spectra and SEM, the mechanisms of the reduction of both the critical temperature and the strength of P tr peak for the Fe-18Ga- x La alloy are ascribed to the precipitation of LaGa2 phase, which reduces the Ga content gradually in the matrix. Further, the mechanism is verified in Fe-18.1Ga alloy and Fe-19.3Ga alloy. In addition, the trace La doping can significantly improve the mechanical strength of the Fe − 18Ga alloy. Highlights: A series of IF peaks were observed in Fe-18Ga- x La alloy. Trace La doping has a significant effect on the P tr peak. The mechanism of the reduction of the peak position is ascribed to the precipitation of LaGa2 phase. Trace La doping can significantly improve the mechanical strength.