Investigation on two Ti–B-reinforced Al alloys for Laser Powder Bed Fusion

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2021-03, Vol.808, p.140944, Article 140944
• Main Authors: Belelli, F., Casati, R., Larini, F., Riccio, M., Vedani, M.
• Format: Article
• Language: English
• Subjects: Additive manufacturing; Aerospace industry; Aging; Alloy powders; Alloys; Aluminium alloys; Aluminum base alloys; Chemical composition; Copper; Forging; Grains; Heat resistant alloys; High strength alloys; High temperature; High temperature applications; Laser powder bed fusion; Lasers; Magnesium; Mechanical properties; Microstructure; Parameter modification; Powder beds; Solidification; Tensile strength; Ultimate tensile strength; Yield strength; Yield stress
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2021.140944

and high-strength aluminium alloys can be processed by Laser Powder Bed Fusion without forming solidification cracks. This constraint limits the diffusion of this technology in many industrial fields, including aerospace and motorsport sectors. In this study, a novel high-strength aluminium alloy for Laser Powder Bed Fusion was designed and its solidification behavior, microstructure and mechanical performance were investigated. The results were compared with those achieved by processing the high-strength A20X alloy processed with the same technology. The alloy was designed based on the chemical composition of the widely used 2618 Al alloy, a conventional high strength Al–Cu–Mg alloy for high temperature applications. The chemical composition of the 2618 alloy was modified by adding Ti and B, which form TiB2 particles that act as nuclei for the solidification of primary α-Al grains. The resulting microstructure made of equiaxed grains revealed resistant to hot cracking. A20X and 2618-modified alloys produced with optimized parameters featured relative densities higher than 99,7% and crack-free microstructures. The A20X-T6 showed yield strength and ultimate tensile strength of 428 MPa and 485 MPa, respectively, while the modified 2618-T6 revealed upper yield strength and ultimate tensile strength of 370 MPa and 468 MPa, respectively. The two alloys also showed a remarkably high strength at 150 °C and 250 °C, exceeding the typical strength values of the 2618 alloy produced by forging.