Effects of forming parameters on microstructure and mechanical properties of a cup-shaped Mg–8.20Gd–4.48Y–3.34Zn–0.36Zr alloy sample manufactured by thixoforming
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Thixoforming experiments of a cup-shaped Mg–8.20Gd–4.48Y–3.34Zn–0.36Zr alloy sample were carried out on a hydraulic press at different temperatures under different forming loads. Metallographic analysis, Vickers hardness test, and tensile tests were conducted to investigate the microstructure and mechanical properties of the samples formed under different forming parameters. Samples without macro- and micro-defects formed successfully at 580 °C under different forming loads were attributed to the excellent formability of semisolid slurry with homogeneous globular microstructure. Because solid and liquid phases in the semisolid slurries exhibited different forming behaviors during thixoforming, liquid segregation occurred and resulted in the inhomogeneous microstructural distribution in thixoformed samples. Owing to the different crystal structures of α-Mg and (Mg, Zn)3RE eutectic compounds transformed from liquid phase, their volume fraction, morphologies, and distributions affected the mechanical properties of the thixoformed samples significantly. Neither formability of semisolid slurry nor the microstructure of thixoformed sample was affected significantly by the forming load. Higher values of Vickers hardness measured in the bottom regions of the sample formed under higher forming loads were attributed to the higher residual stress caused by the excess forming energy.
KeywordsThixoforming Mg-RE alloy Semisolid forming Mechanical properties
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This study was financially supported by National Natural Science Foundation of China (contract No. 51605055), Chongqing Natural Science Foundation (contract No. cstc2016jcyjA1027), Fundamental Research Funds for the Central Universities (contract No. 0903005203307), and Venture & Innovation Support Program for Chongqing Overseas Returnees.
- 28.Young KP, Kyonka CP, Courtois JA (1983) Fine grained metal composition. US Patent 4,415,374Google Scholar
- 29.Kirkwood DH, Sellars CM, Eliasboyed LG (1991) Fine grained metal composition. US Patent 5,037,498Google Scholar