Strengthening and deformation mechanism of selective laser-melted high-concentration nitrogen solute α-Ti materials with heterogeneous microstructures via heat treatment

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:826

Article

Issariyapat, Ammarueda¹  Bahador, Abdollah¹  Visuttipitukul, Patama²  Li, Shufeng³  Umeda, Junko¹  Kondoh, Katsuyoshi¹ 

[1] Osaka Univ, Joining & Welding Res Inst, 11-1 Mihogaoka, Ibaraki, Osaka 5670047, Japan

[2] Chulalongkorn Univ, 254 Phayathai Rd, Bangkok 10330, Thailand

[3] Xian Univ Technol, 19 Xianning Rd, Xian 710048, Shaanxi, Peoples R China

关键词: Titanium-Nitrogen;    Selective laser melting;    Heat treatment;    Heterogeneous microstructure;    Deformation mechanism;   

DOI  :  10.1016/j.msea.2021.141935

来源: Elsevier

【 摘 要 】

Light elements such as oxygen (O) and nitrogen (N) significantly impact the microstructure and mechanical properties of Ti-based materials through solid solution strengthening. The microstructures of Ti-based materials processed via selective laser melting (SLM) have also been observed to contain a martensitic phase that improves the tensile strength. However, this improvement is achieved at the cost of reduced ductility. This study considered the use of post-heat treatment N dissolution to enhance the ductility of SLM-processed alpha-Ti materials. Tensile testing of the as-fabricated SLM Ti-(N) revealed a significantly increased strength of similar to 1200 MPa and a low ductility of 5% for N content of 0.5 wt%. However, the quenched samples exhibited increased ductility by up to 20%, with the microstructure, including primary alpha(alpha(p)) and transformed beta structures. Further examination via electron probe micro-analysis (EPMA), transmission electron microscopy (TEM), in-situ high-temperature SEM observation and in-situ EBSD observation during tensile testing revealed that the enhancement in ductility of the quenched SLM-processed Ti-(N) samples was significantly due to alteration of the grain morphology, dislocations and N distribution. The findings of this study further clarify the microstructural evolution and deformation response of SLM-processed Ti-(N) materials under water quenching.

【 授权许可】

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