Microstructure and properties of Ni-Co-Mn-Al magnetic shape memory alloy prepared by direct laser deposition and heat treatment. (September 2021)

• Record Type: Journal Article
• Authors: Jia, Wuming; Chen, Suiyuan; Wang, Luting; Shang, Fanmin; Sun, Xinru; Yang, Dongrui
• Is Part Of: Optics & laser technology. Volume 141(2021)
• Publication Date: 2021-09
• Subjects: Direct laser deposition -- Ni-Co-Mn-Al magnetic shape memory alloy -- Martensitic transformation -- Crack -- Heat treatment; Optics -- Periodicals; Lasers -- Periodicals; Electronic journals; 621.366
• DOI: 10.1016/j.optlastec.2021.107119
• Languages: English
• ISSNs: 0030-3992

Abstract

Highlights: The Ni-Co-Mn-Al alloys with good formability were successfully prepared by DLD. The microstructure evolution of DLD Ni-Co-Mn-Al alloys was clearly clarified. The factors affecting the phase transition of DLD Ni-Co-Mn-Al alloys were analyzed. The Ni-Co-Mn-Al alloys with phase change and good mechanical property were obtained. Abstract: Ni-Co-Mn-Al magnetic shape memory alloys (MSMAs) has significant application prospects in driving, sensing, and refrigeration, however, its brittleness and difficulty in processing restrict the rapid development of applications. In this paper, the Ni-Co-Mn-Al alloy was prepared by laser direct deposition (DLD) and subsequent heat treatment (HT). The formability, microstructure, and properties of the samples were studied. The results show that the Ni-Co-Mn-Al alloy samples without obvious defects but with good formability were successfully prepared under the optimized DLD parameters. The deposited sample structure was composed of L10 martensite and 24.1 vol% γ[(Co, Ni)Mn] phase, and its compressive strength was 1785 MPa and the maximum compressive strain was 30.3%. Amounts of γ phases in the DLD samples hindered the martensitic transformation (MT). However, after HT at 850 °C for 16 h, the alloy sample structure was composed of L10 martensite and 3.5 vol% γ(Mn-rich) phase. The reduction of the γ phase promoted the MT so that the prepared Ni-Co-Mn-Al alloy be provided with characteristics of reversible MT. Meanwhile, the compressive strength of the sample reached 1295 MPa and the maximum compressive strain was 20.7%. The Ni-Co-Mn-Al alloy with representative phase transformation and good mechanical properties had been obtained.