Very high cycle fatigue of laser powder bed fused Al-Cu-Mg-Ag-TiB2 (A20X) Alloy: Stress relief and aging treatments

• Published in: International journal of fatigue Vol. 183; p. 108281
• Main Authors: Avateffazeli, Maryam, Shakil, Shawkat I., Behvar, Alireza, Attallah, Moataz M., Simsiriwong, Jutima, Tridello, Andrea, Paolino, Davide S., Haghshenas, Meysam
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-06-2024
• Subjects: A20X; Al-Cu-Mg-Ag-TiB2; Laser powder bed fusion; Ultrasonic fatigue; Very high cycle fatigue; Very high cycle fatigue; LEVD; EBSD; ANOVA; EDS; S-N; DOF; SR; Al-Cu-Mg-Ag-TiB2; Laser powder bed fusion; FGA; T7; cdf; MS; A20X; FCC; USF; HCF; P-S-N; LPBF; AM; Ultrasonic fatigue; ICI; LCF; SIF; PF; SEM; VHCF; IPF
• ISSN: 0142-1123; 1879-3452
• DOI: 10.1016/j.ijfatigue.2024.108281

•Unveiling VHCF behavior of laser powder bed fused A20X, a novel Al-Cu-Mg-Ag-TiB2 alloy.•Experimental revelation of asymptotic trend at 109 cycles.•Insights into defect/microstructure influence on enhanced fatigue performance.•Fisheye morphology observed, revealing internal crack-initiating site.
This study presents a comprehensive exploration of the fatigue response in the very high cycle fatigue (VHCF) regime for an additively manufactured (i.e., laser powder bed fused) A20X aluminum alloy. Although the need for high-performance materials with exceptional fatigue qualities has increased dramatically, the VHCF behavior of Al-Cu-Mg-Ag-TiB2 (A20X) structures remains largely unknown. A series of ultrasonic fatigue tests were performed to assess the prolonged fatigue life of the A20X alloy (in the VHCF domain where the number of cycles to failure is beyond 10 million cycles). The VHCF response, assessed through ultrasonic fatigue testing, was investigated by examining the stress-life (S-N) curves in a statistical framework, the fatigue crack initiation and propagation behavior, and the fracture surfaces. An asymptotic trend was experimentally found at 109 cycles, with a stress amplitude of 110 MPa for stress-relieved (SR) and 125 MPa for artificially aged (T7) materials, indicating the presence of an endurance limit. Furthermore, fracture surfaces showed the typical fisheye morphology, with a fine granular area (FGA) containing an internal crack-initiating site. The findings of this paper can assist in optimizing fatigue and durability design allowable for applications for extended fatigue life in the VHCF domains.