Altered phase transformation behaviors and enhanced bending shape memory property of NiTi shape memory alloy via selective laser melting

Lu, H.Z.; Ma, Hongwei; Cai, Wei; Luo, Xiaoxiao; Qu, Shengguan; Wang, J.; Lupoi, Rocco; Yin, Shuo; Yang, Chao

doi:10.1016/j.jmatprotec.2022.117546

Cited by 31 publications

(7 citation statements)

References 31 publications

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“…The strong diffraction peaks of NiTi phase B2 (JCPDS Card #18–0899) appear in all the tested samples. With the decrease of scanning speed, the diffraction peaks of B19’ martensite phase (JCPDS Card #35–1281) emerged gradually (Lu et al , 2022) Meanwhile, it can be found that the Ti 2 Ni (JCPDS Card #18–0898) and Ni 4 Ti 3 (JCPDS Card #39–1113) precipitates are existed in all samples. Figure 6 shows the microstructure of SLM-printed NiTi samples under 140 W, 400 mm/s and 140 W, 700 mm/s.…”

Section: Resultsmentioning

confidence: 99%

“…In addition, Particularly, the Ms decreases from 48°C to 12.5°C, with a decrease of more than 35°C. The decrease of Ms means transforming the martensite phase B19' to the austenite phase B2 is easier at room temperature (Lu et al, 2022). Meanwhile, phase B2 can be transformed into phase B19' during the stress process.…”

Section: Densification Behavior Under Different Process Parametersmentioning

confidence: 99%

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Study on phase transformation behavior and mechanical properties of equiatomic ratio NiTi alloy formed by selective laser melting

Song

Huang²,

Liu³

et al. 2022

RPJ

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Purpose This paper aims to better control the mechanical properties and functional properties of NiTi alloy. Design/methodology/approach NiTi alloy samples with equal atomic ratio were formed by selective laser melting (SLM). X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy and tensile testing methods were used to study the effects of different laser power and scanning speed on the densification behavior, phase transformation characteristics and mechanical properties of NiTi alloy. Findings Compared with the laser power, the variation of the keyhole effect caused by the change of scanning speed is more intense, which has a greater effect on the densification behavior of SLM NiTi alloy. The effect of the laser power on the phase transition temperature is small. The increase of scanning speed weakens the burning degree of Ni element, so phase transition temperature decreases. The results of DSC test and tensile test show that the scanning velocity can significantly change the phase transition temperature, martensite twins reorientation and stress–strain behavior of SLM NiTi alloy. Originality/value This study provides a potential method to regulate the mechanical properties and functional properties of NiTi shape memory alloy in the future and NiTi alloys formed by SLM with good elongation were obtained because the Supercellular crystal structure formed during the nonequilibrium solidification of SLM and the superfine precipitates dispersed in the alloy prevented the dislocation formation.

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Section: Resultsmentioning

confidence: 99%

Section: Densification Behavior Under Different Process Parametersmentioning

confidence: 99%

Study on phase transformation behavior and mechanical properties of equiatomic ratio NiTi alloy formed by selective laser melting

Song

Huang²,

Liu³

et al. 2022

RPJ

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“…The roughness may be decreased, and the shape recovery efficiency enhanced by polishing or additional post-processing, such as surface treatment. SLM NiTi can be heat-treated to enhance the shape memory response include [123]. Heat treatments can enhance shape memory characteristics, as well as adjust the microstructure and alter phase transformation temperatures.…”

Section: Selective Laser Melting (Slm)mentioning

confidence: 99%

Processing of shape memory alloys research, applications and opportunities: a review

Mehta,

Singh,

Vasudev

2024

Phys. Scr.

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Shape Memory Alloys (SMAs) are metallic materials with unique thermomechanical characteristics that can regain their original shape after deformation. SMAs can be used in various industries such as consumer electronics, automobile parts, aircraft components, and biomedical devices. In this paper, we review the current state of the art of SMA fabrication and their application in the aerospace, healthcare, and aerospace industries. Specifically, we focus on the influence of manganese (Mn) addition on Cu-Al-Ni shape memory alloys' structure, mechanical characteristics, and corrosion behavior, focusing on the incorporation of small and medium-sized enterprises (SMEs) in the analysis of cu-aluminum alloys. This study explores the integration of SME and superelasticity, critical phenomena in SMA behavior, and can be utilized to develop and evaluate SMA-based devices and structures, as well as to understand the mechanism behind SMA actuation and develop improved materials. FEM simulations are crucial for optimizing designs and enhancing performance in sectors like aerospace and healthcare. FEM simulations can also be used to predict the stress and strain of SMA-based devices and structures. This can help to reduce cost, improve efficiency, and reduce the risk of failure. Additionally, FEM simulations can help to identify potential weaknesses in SMA-based designs and suggest modifications or improvements.

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“…It is well known that laser processing parameters have a significant effect on the forming quality, solidified microstructure, phase transformation behavior and functional properties (superelasticity effect and shape memory effect) of NiTi alloys. A plenty of studies have been conducted to establish the relationship between the laser processing parameters and the forming quality, transformation temperatures (TTs) and functionalities of NiTi-based bulk samples [15,23,24]. Their results reveal that the processing parameter optimization can not only help to eliminate the metallurgical defects (e.g.…”

Section: Introductionmentioning

confidence: 99%

Understanding the role of laser processing parameters and position-dependent heterogeneous elastocaloric effect in laser powder bed fused NiTi thin-walled structures

Peng,

Ma,

Yuan

et al. 2024

Smart Mater. Struct.

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To reduce the driving load and enhance the heat exchange capacity and elastocaloric refrigeration efficiency, increasing interests in porous structure design and laser-based additive manufacturing (LAM) of NiTi materials with a large specific surface area have been emerging. As a type of characteristic unit of porous components, we mainly focused on the LAM process optimization and elastocaloric effect of NiTi-based thin-walled structures (TWSs) in this work. Firstly, we systemically studied the influence of laser processing parameter on the forming quality and phase transformation behavior of NiTi-based TWS samples. Results showed that high relative density (>99.0%) was inclined to be obtained in a range of 67-133 J/mm3 (laser energy density). Besides, the transformation temperatures (TTs) and enthalpy change roughly showed a positive linear relationship with the applied laser energy density. At an optimized parameter (P=100 W and v=1000 mm/s), the sample exhibited a high relative density (99.88%), good dimensional accuracy, and the lowest TTs. Then, this work emphatically unveiled the position-dependence of phase transformation behavior and elastocaloric effect (eCE) in a NiTi-based TWS sample. It was found that both the TTs and enthalpy change monotonously decreased along the building direction, while the transformation strain kept an increase trend. As a result, the middle portion of the sample exhibited the largest adiabatic temperature change which reached 6.5 K at the applied stain of 4%. The variation in TTs and eCE could be attributed to the heterogeneous solidification microstructure induced by the thermal cycle nature of LAM process.

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Altered phase transformation behaviors and enhanced bending shape memory property of NiTi shape memory alloy via selective laser melting

Cited by 31 publications

References 31 publications

Study on phase transformation behavior and mechanical properties of equiatomic ratio NiTi alloy formed by selective laser melting

Study on phase transformation behavior and mechanical properties of equiatomic ratio NiTi alloy formed by selective laser melting

Processing of shape memory alloys research, applications and opportunities: a review

Understanding the role of laser processing parameters and position-dependent heterogeneous elastocaloric effect in laser powder bed fused NiTi thin-walled structures

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