Effect of volume energy density on selective laser melting NiTi shape memory alloys: microstructural evolution, mechanical and functional properties

Ge, Jinguo1,2; Yuan, Bo1; Zhao, Lun1; Yan, Ming3; Chen, Wei1; Zhang, Liang1

2022-10-01

10.1016/j.jmrt.2022.08.062

Journal of Materials Research and Technology-JMR&T   Impact Factor & Quartile

2238-7854

2214-0697

Equi-atomic NiTi shape memory alloy (SMA) samples were manufactured by selective laser melting (SLM) with different laser volume energy densities via synchronously varying laser power and scanning speed. The processing quality, phase transformation, and micro -structural evolution were investigated to explore the mechanisms that are responsible for mechanical and functional properties. The results showed scattered micro-sized spherical gaseous defects inside the deposit. One-stage phase transformation occurred without in-termediate R-phase transition, and the temperature of both endothermic and exothermic peaks was lower than that of the ingot. The microstructure initially grew along the building direction, but displayed different crystal orientations between coarse columnar grains and refined irregular sub-grains. The micro-hardness mapping revealed that homogenous anti -indentation properties were acquired independent of location variations. While the anisotropic behavior in tensile properties occurred due to the passive effect of columnar B2 austenitic grains, a synergistic effect of strength and plasticity was acquired primarily due to the combined effect of sub-grain refinement strengthening and transformation-induced plasticity. The pre-deformed NiTi samples recovered to their original shape when heated above its critical phase transition point. This work demonstrated that the crack-free NiTi SMA with exceptional comprehensive performances could be fabricated by SLM through the control of energy density.(c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

NiTi shape Memory alloy Selective laser melting Laser volume energy density Microstructural evolution Mechanical and functional performance

SCI

English

Others

China Postdoctoral Science Foundation[2021M693230] ; Natural Science Foundation of Guangxi Province[2021JJB160022] ; ShenZhen Science and Technology Innovation Commission[JCYJ20190809103803675] ; Post -doctoral Foundation Project of Shenzhen Polytechnic[6021330015K0] ; National Science Foundation of Guangdong Province[2020A1515010257] ; Guangdong Provincial General University Innovation Team Project[2020KCXTD047]

Materials Science ; Metallurgy & Metallurgical Engineering

Materials Science, Multidisciplinary ; Metallurgy & Metallurgical Engineering

WOS:000863019700001

ELSEVIER

Web of Science

1.ShenZhen Polytech, Inst Intelligent Mfg Technol, Shenzhen 518055, Peoples R China
2.Guilin Univ Elect Technol, Sch Mech & Elect Engn, Guilin, Peoples R China
3.Southern Univ Sci & Technol, Dept Mat Sci & Engn, Shenzhen Key Lab Addit Mfg High Performance Mat, Shenzhen 518055, Peoples R China

Ge, Jinguo,Yuan, Bo,Zhao, Lun,et al. Effect of volume energy density on selective laser melting NiTi shape memory alloys: microstructural evolution, mechanical and functional properties[J]. Journal of Materials Research and Technology-JMR&T,2022,20.

Ge, Jinguo,Yuan, Bo,Zhao, Lun,Yan, Ming,Chen, Wei,&Zhang, Liang.(2022).Effect of volume energy density on selective laser melting NiTi shape memory alloys: microstructural evolution, mechanical and functional properties.Journal of Materials Research and Technology-JMR&T,20.

Ge, Jinguo,et al."Effect of volume energy density on selective laser melting NiTi shape memory alloys: microstructural evolution, mechanical and functional properties".Journal of Materials Research and Technology-JMR&T 20(2022).