Enhancement of mechanical properties in AZ91D magnesium alloy via wire arc additive manufacturing: influence of rapid solidification and solute segregation on microstructure and deformation behavior
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引用次数: 0
Abstract
The short-process fabrication of high-performance magnesium alloys holds great promise for aerospace and automotive applications, driving advancements in high-end manufacturing. In this study, tungsten inert gas (TIG)-protected wire arc additive manufacturing (WAAM) was employed to produce AZ91D Mg alloy with a weakly textured, equiaxed grain structure. The resulting alloy exhibits an ultimate tensile strength of 284 MPa and uniform elongation of 12.5%, facilitated by enhanced work hardening. Optimized solidification conditions "freeze" solute atoms in a supersaturated state, inhibiting diffusion and precipitation, and result in a heterogeneous solute distribution. The elevated Al solute concentration suppresses twin propagation, leading to the formation of refined twin lamellae. The ensuing interactions between these fine twins and dislocations play a pivotal role in enhancing the work hardening capability. Additionally, the gradient distribution of Al solute atoms, together with the grain boundary segregation of Al/Zn, effectively weakens the texture, thereby preserving the mechanical isotropy of the WAAM-AZ91D alloy. Additionally, a gradient distribution of solid solution Al atoms extending from grain boundaries to the interior establishes a hardness gradient, effectively alleviating stress concentrations at grain boundaries during deformation and enabling uniform plastic deformation of WAAM-AZ91D. This work expands the application of post-treatment-free short-process fabrication techniques as an effective strategy for the rapid production of high-performance magnesium alloys, broadening their application scope.
期刊介绍:
International Journal of Plasticity aims to present original research encompassing all facets of plastic deformation, damage, and fracture behavior in both isotropic and anisotropic solids. This includes exploring the thermodynamics of plasticity and fracture, continuum theory, and macroscopic as well as microscopic phenomena.
Topics of interest span the plastic behavior of single crystals and polycrystalline metals, ceramics, rocks, soils, composites, nanocrystalline and microelectronics materials, shape memory alloys, ferroelectric ceramics, thin films, and polymers. Additionally, the journal covers plasticity aspects of failure and fracture mechanics. Contributions involving significant experimental, numerical, or theoretical advancements that enhance the understanding of the plastic behavior of solids are particularly valued. Papers addressing the modeling of finite nonlinear elastic deformation, bearing similarities to the modeling of plastic deformation, are also welcomed.