Compositionally graded titanium to aluminum processed by laser powder bed fusion process: Microstructure evolution and mechanical properties

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 903; p. 146638
• Main Authors: Daram, Phuangphaga, Singh, Alok, Hiroto, Takanobu, Kitashima, Tomonori, Watanabe, Makoto
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-06-2024
• Subjects: Compositionally graded materials; Laser powder bed fusion process; Mechanical properties; Microstructure; Ti–Al alloy; Mechanical properties; Compositionally graded materials; Ti–Al alloy; Microstructure; Laser powder bed fusion process
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2024.146638

A compositionally graded Ti–Al alloy with a designed composition range from pure Ti to pure Al was successfully produced by a laser powder bed fusion (L-PBF) system equipped with two powder feeders. The compositionally graded Ti–Al profile is confirmed by scanning electron microscopy, X-ray diffraction analysis, electron backscatter diffraction microscopy, and transmission microscopy. The graded material is free of macro-horizontal cracks, but micro-cracks appear at the center of the sample. Varying the Ti and Al ratio along the build direction induces microstructural changes, transforming α+β-Ti into solid solution, creating intermetallics (Ti and Al), and yielding an Al phase with diverse morphologies. Additionally, the Ti–Al ratio's influence on microstructure formation and phase evolution results in varying mechanical properties among the graded material's layers. The results demonstrate that the L-PBF process can achieve continuous compositional grading of Ti–Al materials in a single run. Moreover, this study hold the potential to facilitate the design and production of numerous compositional variants for high entropy alloys and multi-materials, enabling future investigation into microstructural evolution, phase transformation, and physical and mechanical properties.