Influence of texture on superplastic behavior of friction stir processed ZK60 magnesium alloy

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2012-10, Vol.556, p.671-677
• Main Authors: Yang, Q., Feng, A.H., Xiao, B.L., Ma, Z.Y.
• Format: Article
• Language: English
• Subjects: Applied sciences; Cross-disciplinary physics: materials science; rheology; Deformation, plasticity, and creep; Elasticity. Plasticity; Elongation; Exact sciences and technology; Friction stir processing; Magnesium alloys; Magnesium base alloys; Materials science; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Other heat and thermomechanical treatments; Physics; Plastic deformation; Superplastic forming; Superplasticity; Surface layer; Texture; Treatment of materials and its effects on microstructure and properties; Yield strength
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2012.07.046

Commercial ZK60 extruded plate was subjected to friction stir processing (FSP). A fine-grained structure 2.9μm in grain size with uniformly distributed fine second-phase particles and predominant high-angle grain boundaries of 97% was obtained. A strong basal fiber texture with the (0002) planes roughly surrounding the tool pin surface was developed in the FSP ZK60 alloy. The FSP ZK60 alloy exhibited superplastic behavior at 225–325°C in both the transverse direction (TD) and longitudinal direction (LD), with the superplastic elongation in the LD being higher than that in the TD. A maximum elongation of 1390% was obtained at 300°C and 3×10−4s−1 in the LD. The existence of texture was found to influence the superplastic flow stress and plasticity. The texture had a minor influence on the flow stress, due to the texture weakening during superplastic deformation. However, the anisotropy of plasticity existed at all temperatures and strain rates, as a result of the activation of different slip systems in different tensile directions.