Effect of Processing Parameters on Microstructure and Macroscopic Properties of Ni-Ti Alloys Fabricated by Selective Laser Melting

doi:10.3901/JME.260080

Abstract

Abstract: Ni-Ti shape memory alloys (SMAs) are fabricated by selective laser melting (SLM) technology. The effects of laser power, scanning velocity, and volumetric energy density on the forming quality, microstructure, martensitic transformation behavior, mechanical properties, and superelasticity of SLM-fabricated Ni-Ti SMAs are systematically investigated. The results indicate that to achieve a relative density above 99%, a high laser power should be combined with a high scanning velocity, while a low laser power should be paired with a low scanning velocity. Additionally, a minimum volumetric energy density of 45 J/mm³ is required. Regardless of the processing parameters used, columnar grains aligned parallel to the build direction formed in all SLM-fabricated Ni-Ti SMAs when an x/y alternating scanning strategy is applied. And both the length and width of columnar grains increased as the volumetric energy density increased, which corresponds to higher laser power and lower scanning velocity. Moreover, with increasing the volumetric energy density, the characteristic temperatures of martensitic transformation of SLM-fabricated Ni-Ti SMAs increased, and the critical stress for stress-induced martensitic transformation consequently decreased. Samples fabricated with a low energy density of volumetric 57.1 J/mm³ exhibited a nominal yield strength of 1 208 MPa and a superelastic recovery strain of 6.9% under room-temperature compression. As the volumetric energy density further increased, the nominal yield strength first increased and then decreased, while the superelastic recovery strain consistently declined.

Key words: selective laser melting, Ni-Ti alloy, shape memory alloy, superelasticity, martensitic transformation

CLC Number:

TG139
TG665

ZENG Xiangxu, LI Zhaoqing, ZHANG Zhengyan, LI Yipeng, LIN Kun, YANG Xiao. Effect of Processing Parameters on Microstructure and Macroscopic Properties of Ni-Ti Alloys Fabricated by Selective Laser Melting[J]. Journal of Mechanical Engineering, 2026, 62(3): 203-217.

References

[1] 严鲁涛，王琦，李海源，等. 基于形状记忆合金驱动的连续体机器人路径规划[J]. 机械工程学报，2023，59(15)：50-61. YAN Lutao，WANG Qi，LI Haiyuan，et al. Path planning of continuum robot actuated by shape memory alloy[J]. Journal of Mechanical Engineering，2023，59(15)：50-61.
[2] XU L，ZHU M，ZHAO J，et al. The utilization of shape memory alloy as a reinforcing material in building structures：A review[J]. Materials，2024，17(11)：2634.
[3] WAIDI Y O. Recent advances in 4D-printed shape memory actuators[J]. Macromolecular Rapid Communications，2025，46(10)：2401141.
[4] SIMA Y，WANG W，ABU-TAHON M A，et al. An overview of 3D-printed shape memory alloys and applications in biomedical engineering[J]. Advanced Composites and Hybrid Materials，2024，7(5)：148.
[5] QIN Y，WANG T，XIN J，et al. Research progress of shape memory alloy reinforced cement-based composites materials and its components[J]. Materials Review，2024，38(10A)：23060190-9.
[6] HANG R，ZHAO F，YAO X，et al. Self-assembled anodization of NiTi alloys for biomedical applications[J]. Applied Surface Science，2020，517：146118.
[7] TOGHANI-TAHERI F，KHODABAKHSHI F，MALEKAN M，et al. Cyclic pseudoelastic behavior of friction stir processed NiTi shape memory alloy：Microstructure and W-alloying[J]. Materials Science and Engineering：A，2025，927：148000.
[8] OM H，SINGH S. Fabrication and characterization of vacuum induction-melted cast NiTiCu shape memory alloy[J]. Journal of Mechanical Science and Technology，2025，39：2681–2687.
[9] VOLODKO S，MARKOVA G，YUDIN S，et al. Torsional behavior of Ni-rich NiTi alloys obtained by powder metallurgy and hot deformation[J]. Scientific Reports，2024，14：28431.
[10] TEVES CORDOVA A V I，ALCALDE M P，VIVAN R R，et al. Impact of metallurgical features and cross-sectional design on the cyclic and torsional properties of NiTi rotary instruments[J]. Journal of Materials Research and Technology，2025，36：7740-7747.
[11] BOGATOV Y V，SHCHERBAKOV V A，KOVALEV D Y，et al. Self-propagating high-temperature synthesis compaction of titanium nickelate：Effect of oxygen and hydrogen impurities on the structure and properties of the alloys[J]. Inorganic Materials，2025，90：960-969.
[12] BAIGONAKOVA G A，MARCHENKO E S，MAMAZAKIROV O，et al. Porosity and phase composition effects on SHS-NiTi structure and mechanical properties[J]. Advanced Powder Technology，2024，35：104395.
[13] ADDESS A，SHILO D，GLASS B，et al. Additive manufacturing of Ni–Ti SMA by the sinter-based moldjet method[J]. Shape Memory and Superelasticity，2025，11(1)：89-99.
[14] SIMA Y，WANG W，ABU-TAHON M A，et al. An overview of 3D-printed shape memory alloys and applications in biomedical engineering[J]. Advanced Composites and Hybrid Materials，2024，7(5)：148.
[15] CHEN Y，LI W，ZHANG C，et al. Recent developments of biomaterials for additive manufacturing of bone scaffolds[J]. Advanced Healthcare Materials，2020，9(23)：2000724.
[16] GUO Yunting，LIU Mengqi，JIANG Chaorui，et al. Effect of annealing on the shape memory effect and mechanical properties of laser powder bed fusion NiTi alloy[J]. Additive Manufacturing Frontiers，2025，4(1)：200189
[17] BARBA D，ALABORT E，REED R. Synthetic bone：Design by additive manufacturing[J]. Acta Biomaterialia，2019，97：637-656.
[18] WALKER J M，HABERLAND C，TAHERI ANDANI M，et al. Process development and characterization of additively manufactured nickel–titanium shape memory parts[J]. Journal of Intelligent Material Systems and Structures，2016，27(19)：2653-2660.
[19] CHRISTOPH H，MOHAMMAD E，JASON M W，et al. On the development of high quality NiTi shape memory and pseudoelastic parts by additive manufacturing[J]. Smart Materials and Structures，2014，23：104002.
[20] BORMANN T，MÜLLER B，SCHINHAMMER M，et al. Microstructure of selective laser melted nickel–titanium[J]. Materials Characterization，2014，94：189-202.
[21] YAN J，CAI B，OU B，et al. Effect of laser energy density on the phase transformation behavior and functional properties of NiTi shape memory alloy by selective laser melting[J]. Journal of Alloys and Compounds，2024，1005：176060.
[22] DADBAKHSH S，SPEIRS M，KRUTH J P，et al. Influence of SLM on shape memory and compression behaviour of NiTi scaffolds[J]. CIRP Annals，2015，64：209-212.
[23] DADBAKHSH S，SPEIRS M，KRUTH J P，et al. Effect of SLM parameters on transformation temperatures of shape memory nickel titanium parts[J]. Advanced Engineering Materials，2014，16：1140-1146.
[24] HOU M，GU Q，YANG Z，et al. Enhancing shape memory properties of 3D-printed NiTi alloys by laser powder bed fusion through microstructural control[J]. Journal of Alloys and Compounds，2025，1010：178029.
[25] 汪良，张亮，吴文恒. 激光能量密度和固溶处理对激光选区熔化NiTi合金显微组织和性能的影响[J]. 机械工程材料，2025，49(3)：81-87. WANG Liang，ZHANG Liang，WU Wenheng. Effect of laser energy density and solid solution on microstructure and properties of selective laser melted NiTi alloy[J]. Materials for Mechanical Engineering，2025，49(3)：81-87.
[26] YANG X，CHENG L，PENG H，et al. Development of Fe-Mn-Si-Cr-Ni shape memory alloy with ultrahigh mechanical properties and large recovery strain by laser powder bed fusion[J]. Journal of Materials Science & Technology，2023，150：201-216.
[27] YANG L，SHEN S，DAI J，et al. Effect of laser energy density on the porosity and mechanical properties of SLM formed TA15 alloy[J]. Applied Laser，2025，45(1)：36-45.
[28] YANG Yongqiang，JIANG Renwu，HAN Changjun，et al. Frontiers in laser additive manufacturing technology[J]. Additive Manufacturing Frontiers，2024，3(4)：200160.
[29] MANIKANDAN P，VENKATESAN K. The influence of linear energy density on density，defect formation，residual stress，microstructure，and texture in 310 austenitic stainless steel by laser powder bed fusion[J]. Journal of Manufacturing Processes，2024，131：2191-2207.
[30] HUANG M，YANG B，ZHOU Y，et al. Effect of processing parameters on tensile properties and microstructure of selective laser melted AlSi10Mg alloy[J]. Journal of Materials Engineering and Performance，2025，34(7)：6001-6014.
[31] 杨超，卢海洲，马宏伟，等. 选区激光熔化NiTi形状记忆合金研究进展[J]. 金属学报，2023，59(1)：55-74. YANG Chao，LU Haizhou，MA Hongwei，et al. Research and development in NiTi shape memory alloys fabricated by selective laser melting[J]. Acta Metallurgica Sinica，2023，59(1)：55-74.
[32] XU Y，HE Y，HUANG G，et al. Numerical simulation and experimental investigation of the molten pool evolution and defects formation mechanism of selective laser melted CuSn20/diamond composites[J]. Materials & Design，2024，243：113082.
[33] QUAN G，DENG Q，ZHAO Y，et al. Achievement of a parameter window for the selective laser melting formation of a GH3625 alloy[J]. Materials，2024，17(10)：2333.
[34] 宋军，唐倩，罗智超，等. 马氏体时效钢激光选区熔化成形过程介观尺度数值模拟[J]. 机械工程学报，2024，60(3)：282-295. SONG Jun，TANG Qian，LUO Zhichao，et al. Mesoscopic numerical simulation during selective laser melting of maraging steel[J]. Journal of Mechanical Engineering，2024，60(3)：282-295.
[35] WU J，MA J，NIU X，et al. Numerical simulation of selective laser melting of 304 L stainless steel[J]. Metals，2023，13(7)：1212.
[36] LIU Z，ZHAO D，WANG P，et al. Additive manufacturing of metals：Microstructure evolution and multistage control[J]. Journal of Materials Science & Technology，2021，100：224-236.
[37] WANG S，YANG X，CHEN J，et al. Effects of building directions on microstructure，impurity elements and mechanical properties of NiTi alloys fabricated by laser powder bed fusion[J]. Micromachines，2023，14(9)：1711.
[38] WEI S，ZHANG J，ZHANG L，et al. Laser powder bed fusion additive manufacturing of NiTi shape memory alloys：A review[J]. International Journal of Extreme Manufacturing，2023，5：032001.
[39] GARRIDO C，PEROSANZ S，ELLIOTT A，et al. On the effect of the processing parameters in microstructure and thermomechanical properties of LPBF NiTi shape memory alloys[J]. Journal of Materials Research and Technology，2024，33：2414-2429.
[40] LU H，MA H，YANG Y，et al. Tailoring phase transformation behavior，microstructure，and superelasticity of NiTi shape memory alloys by specific change of laser power in selective laser melting[J]. Materials Science and Engineering：A，2023，864：144576.