Effects of quenching process on microstructure, mechanical properties and magnetic susceptibility in Zr1Mo alloy fabricated by powder bed fusion process. (February 2020)

• Record Type: Journal Article
• Authors: Sun, Xiaohao; Liu, Debao; Zhou, Weiwei; Nomura, Naoyuki; Doi, Hisashi; Tsutsumi, Yusuke; Hanawa, Takao
• Is Part Of: Materials & design. Volume 187(2020)
• Publication Date: 2020-02
• Subjects: Powder bed fusion process -- Zr-based alloy -- Quenching process -- Microstructure -- Magnetic resonance imaging compatibility; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2019.108356
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: In order to depress the "susceptibility artifacts" in magnetic resonance imaging (MRI), improve the mechanical reliability for biomedical structural applications and realize tailor-made medical devices with complex shape, low magnetic Zr-1Mo(wt%) alloy builds with high relative density (c.a. 99.9%) fabricated by laser powder bed fusion process(L-PBF) were subjected to various heat treatment conditions followed by water quenching. After quenching process acicular α′ microsturcture in as-build Zr-1Mo(wt%) alloy builds changed to basket weave α + β structure, unique retained α + ultra fine (α′ + α″) martensite structure or retained α + acicular α′ microsturcture depending on quenching conditions. X-ray diffraction (XRD) and high resolution-transmission electron microscope(HR-TEM) revealed a unique retained α + ultra fine (α′ + α″) martensite microstructure in 1123 K specimens. The stress-induced competition between β to α′ transformation and β to α″ transformation contributed to this unique microstructure. This unique microstructure contributed to a good balance between strength (UTS:822 MPa) and ductility (Elongation:11.7%). The volume magnetic susceptibility of quenched Zr-1Mo(wt%) alloy builds maintained low(about 1.01 × 10 −4 ) indicating good MRI compatibility. The magnetic susceptibility of each phase was modified to be χα″ > χβ > χα > χα ′ > χω. Zr-1Mo(wt%) alloy quenched from 1123 K will be an promising candidates for tailor made devices under MRI environments. Graphical abstract: Unlabelled Image Highlights: L-PBF-processed Zr1Mo alloy builds were subjected to various quenching process. A unique retain α + ultra fine (α′α″) structure was confirmed in 1123 K specimens. 1123 K specimens exhibited good balance between strength and ductility. All the quenched Zr1Mo alloy builds maintain low magnetic susceptibility. Phase magnetic susceptibility in Zr was modified to be χα ″ > χβ > χα > χα ′ > χω .