科研之友
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摘要
Based on mechanisms applicable to bulk metallic glasses (BMGs), such as a superposition principle of an instantaneous finite surface heat source temperature field and a flow model about the shear-band velocity, a maximum temperature rise model of shear bands in BMGs was deduced, Delta T-max=sigma(y)/c(p)root Delta u(pl)center dot v(SB)/2 pi alpha. The model de-scribes the dependence of the maximum temperature rise on the yield strength and the shear-band velocity in BMGs. It can be calculated that the maximum temperature rise of BMGs is between 1 K similar to 30 K at room tem-perature through these two parameters. A critical temperature, TC, of almost 0.8 similar to 0.9T(g) is introduced, at T<TC, the change of the yield strength with temperature in BMGs basically conforms a cooperative shear model (CSM), and at T>TC, a significant reduction of the yield strength in BMGs can be attributed to avoiding failure due to localized material softening.
