Investigation on creep mechanical properties and the relationship between creep cavities and deformation activation energy in 6082-T6 aluminum alloy joints welded by ring-spot laser
Year: 2025
Type: article
Abstract: 6082-T6 aluminum alloy welded joints were solution-treated at 480°C and tested for tensile creep at 180°C, 260°C, and 450°C. The creep strain exponent (n) was strongly influenced by temperature and stress, with temperature having a greater impact. Higher temperatures promoted dislocation creep, while dynamic recrystallization at 450°C improved creep properties, reducing the strain exponent. Creep simulations showed void nucleation in stress-concentrated areas, leading to fracture. Increased temperature and stress accelerated void growth, grain boundary sliding, grain fragmentation, and equiaxed structure formation. These structures favored precipitate and Al-Si-O compound formation, causing stress concentration and void/crack growth. Raising temperature from 180°C to 260°C decreased deformation activation energy and creep resistance, while increasing it from 260°C to 450°C enhanced these properties. Higher stress and temperature reduced deformation activation energy, promoting deformation and void growth, which further lowered activation energy. EBSD analysis revealed void growth at grain boundaries, with dislocations accumulating around voids. Prolonged aging facilitated void/dislocation aggregation. At 180°C, the {110}<001> Goss texture dominated; at 260°C, {110}<112> brass and {112}<111> copper textures were prevalent, with the latter being unstable. At 450°C, textures transformed into copper texture, consistent with temperature-dependent creep behavior. Void nucleation and diffusion activation energy were lower than the interface energy of growing voids, with grain boundary short-circuit diffusion being the primary pathway. Higher dislocation density at pores and pore aggregation at high-angle grain boundaries intensified grain boundary/lattice diffusion, likely driving failure at lower energy inputs. Predicted creep life closely matched experimental results, highlighting the need for further study.
Authors: Kuntao Liu, Shanglei Yang, Jieshi Chen, Suqi Xue, Nuo Cheng, Qiubo Li
Institution: Shanghai University of Engineering Science
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,640
OpenAlex ID: W4409722719