Effect of laser energy density on the evolution of Ni4Ti3 precipitate and property of NiTi shape memory alloys prepared by selective laser melting

Gan, Jie; Duan, Lijie; Li, Fēi; Che, Yusi; Zhou, Yan; Wen, Shifeng; Yan, Chunze

doi:10.1016/j.jallcom.2021.159338

Cited by 62 publications

(17 citation statements)

References 38 publications

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“…In Ref. 91, it was shown that the process parameters influence the content and morphology of Ni 4 Ti 3 precipitates. In parts fabricated using low energy density (40 J/mm 3 to 80 J/mm 3 ), fine Ni 4 Ti 3 particles are dispersed uniformly and coherently in the main matrix, while as the energy density increases, the Ni 4 Ti 3 particles become noncoherent, coarse particles with low volume fraction, as illustrated in Fig.…”

Section: Microstructure Of Niti Alloy Processed By Lpbf: Grain Morphology Texture and Precipitationmentioning

confidence: 99%

“…On the other hand, a high energy input results in Ni loss from the matrix and decreases the chance of formation of Ni-rich precipitates. 91 The Ni 3 Ti intermetallic phase is less reported for NiTi alloys processed by LPBF since it can mostly be observed in very Ni-rich NiTi alloys with high Ni concentration (> 51 at.%) close to the eutectic point. 92 However, some works have reported the presence of Ni 3 Ti in Ni-lean NiTi alloy processed by LPBF.…”

Section: Microstructure Of Niti Alloy Processed By Lpbf: Grain Morphology Texture and Precipitationmentioning

confidence: 99%

“…11. 52,63,84,91,[94][95][96][97][98] The data mining focused only on Ni-rich NiTi compositions (Ni > 50.5 at.%) since they are more sensitive to the energy density. The increasing trend of TTs versus energy density saturates at very high levels of energy density, as demonstrated in Fig.…”

Section: Phase Transformation Temperaturesmentioning

confidence: 99%

“…Ni 4 Ti 3 precipitate formation and morphology in NiTi parts processed by LPBF at energy density of (a, d) 37.88 J/mm 3 , (b , e) 79.37 J/ mm 3 , and (c , f) 104.17 J/mm 3 , revealing an increase in the size but decrease in the volume fraction of precipitates with increasing energy density (reprinted with permission from Ref. 91) relationship, the induced internal stress shifts the TTs to higher temperatures. Moreover, the heterogeneous microstructure (i.e., composition, precipitates, and internal stress) of as-built NiTi parts that results from the nonuniform thermal distribution during the LPBF process may broaden the transformation peaks.…”

Section: Phase Transformation Temperaturesmentioning

confidence: 99%

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Additive Manufacturing of NiTi Shape Memory Alloy for Biomedical Applications: Review of the LPBF Process Ecosystem

Safaei

Abedi

Nematollahi

et al. 2021

JOM

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NiTi shape memory alloys (SMAs) are used in a broad range of biomedical applications because of their unique properties including biocompatibility and high corrosion and wear resistance as well as functional properties such as superelasticity and the shape memory effect. The combination of SMAs and additive manufacturing can lead to revolutionary changes to the uses of SMAs in the biomedical industry. This article discusses the potential biomedical applications of NiTi that benefit from the AM process. We share the lessons learned in processing NiTi alloys with a focus on the laser powder bed fusion (LPBF) technique. The manufacturability, build quality, stable phases and transformation temperatures, microstructure, thermomechanical properties, microstructure tailoring, and functional properties of NiTi alloys produced via AM processing are reviewed. Current challenges such as expanding the process window, controlling the chemistry, and the performance and property responses are discussed, and potential opportunities including alloy design are discussed.

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Section: Microstructure Of Niti Alloy Processed By Lpbf: Grain Morphology Texture and Precipitationmentioning

confidence: 99%

Section: Microstructure Of Niti Alloy Processed By Lpbf: Grain Morphology Texture and Precipitationmentioning

confidence: 99%

Section: Phase Transformation Temperaturesmentioning

confidence: 99%

Section: Phase Transformation Temperaturesmentioning

confidence: 99%

See 2 more Smart Citations

Additive Manufacturing of NiTi Shape Memory Alloy for Biomedical Applications: Review of the LPBF Process Ecosystem

Safaei

Abedi

Nematollahi

et al. 2021

JOM

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show abstract

“…For example, rapid solidification promotes the formation of a supersaturated solid solution matrix [25]. At the same time, various process parameters can result in different microstructures and phase composition of nitinol alloys [26], as well as different Ni content resulting in significant changes in transformation behavior [16].…”

Section: Introductionmentioning

confidence: 99%

Microstructure and Mechanical Properties of NiTi-Based Eutectic Shape Memory Alloy Produced via Selective Laser Melting In-Situ Alloying by Nb

Polozov

Popovich

2021

Materials

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This paper presents the results of selective laser melting (SLM) process of a nitinol-based NiTiNb shape memory alloy. The eutectic alloy Ni45Ti45Nb10 with a shape memory effect was obtained by SLM in-situ alloying using a powder mixture of NiTi and Nb powder particles. Samples with a high relative density (>99%) were obtained using optimized process parameters. Microstructure, phase composition, tensile properties, as well as martensitic phase transformations temperatures of the produced alloy were investigated in as-fabricated and heat-treated conditions. The NiTiNb alloy fabricated using the SLM in-situ alloying featured the microstructure consisting of the NiTi matrix, fine NiTi+β-Nb eutectics, as well as residual unmelted Nb particles. The mechanical tests showed that the obtained alloy has a yield strength up to 436 MPa and the tensile strength up to 706 MPa. At the same time, in-situ alloying with Nb allowed increasing the hysteresis of martensitic transformation as compared to the alloy without Nb addition from 22 to 50 °C with an increase in Af temperature from −5 to 22 °C.

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Microstructure and Mechanical Properties of NiTi Shape Memory Alloys by Laser Engineered Net Shaping

Fei

Liu

et al. 2023

Adv Eng Mater

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Herein, NiTi alloys are prepared by laser engineered net shaping (LENS) technology. By exploring the mechanical properties and microstructures of NiTi samples under different laser powers, it is concluded that NiTi alloys with a laser power of 350 W have better tensile strength (783 MPa) and strain recovery rate (59.01%). In addition, the mechanical properties and microstructure of NiTi samples with a laser power of 350 W at different aging temperatures (400–800 °C) are also explored. It is found that NiTi alloys aged at 600 °C had better tensile strength (729 MPa) and strain recovery rate (92.85%). In addition, the phase‐transition temperature and endothermic enthalpy and exothermic enthalpy of the NiTi samples after thermal treatment increased, which is attributed to the formation of stable martensite (B19′) inside the NiTi samples after thermal treatment, and the type of internal NiTi phases structure change significantly. Thermal treatment can generate Ni4Ti3, NiTi2 precipitates, and martensite (B19′) with high density of dislocations inside the NiTi samples. Herein, it is showed that LENS can prepare NiTi alloys with excellent mechanical and structural properties by controlling the equipment parameters and aging temperature.

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Effect of laser energy density on the evolution of Ni4Ti3 precipitate and property of NiTi shape memory alloys prepared by selective laser melting

Cited by 62 publications

References 38 publications

Additive Manufacturing of NiTi Shape Memory Alloy for Biomedical Applications: Review of the LPBF Process Ecosystem

Additive Manufacturing of NiTi Shape Memory Alloy for Biomedical Applications: Review of the LPBF Process Ecosystem

Microstructure and Mechanical Properties of NiTi-Based Eutectic Shape Memory Alloy Produced via Selective Laser Melting In-Situ Alloying by Nb

Microstructure and Mechanical Properties of NiTi Shape Memory Alloys by Laser Engineered Net Shaping

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