Superplastic Deformation Behavior of Zr41.25Ti13.75Ni10Cu12.5Be22.5 Bulk Metallic Glass in Supercooled Liquid Region
نویسندگان
چکیده
This paper presents the tensile deformation behavior of Zr41.25Ti13.75Ni10Cu12.5Be22.5 bulk metallic glass in supercooled liquid region. Isothermal tensile tests are carried out at four characteristic temperatures of 616K, 636K, 656K and 676K which are in the range from glass transition onset temperature to crystallization temperature. The results show that the superplastic flow behaviors of the material, viz., the flow stress and the elongation, vary depending strongly on the testing temperature and initial strain-rate. At a given temperature, the elongation increases firstly and then decreases with the initial strain-rate increasing, and the maximum elongation is found to be as high as 1625% at the temperature of 656K with the strain-rate 7.6×10s. DSC analysis shows that the crystalline volume fraction of deformed section is always higher than that of undeformed section in the specimens. The maximum elongation always corresponds to the maximum crystalline volume fraction. The nanocrystals homogeneously embedded in the amorphous matrix of the deformed specimens can be observed by using TEM. It is resultantly believed that the presence of amorphous-crystalline duplex phase microstructure has a pronounced effect on the superplastic deformation behavior of the material.
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