RESUMO
The mechanical properties of (Cu0.47Zr0.45Al0.08)98Dy2 bulk metallic glass (BMG) were characterized under various strain rates by quasi-static and dynamic compressive tests. In the quasi-static compressive tests, the yield stress of (Cu0.47Zr0.45Al0.08)98Dy2 BMG increased from 1234 MPa to 1844 MPa when the strain rate was increased from 0.001 s-1 to 0.01 s-1, and the yield stress decreased to 1430 MPa at the strain rate of 0.1 s-1. In the dynamic compressive tests, when the strain rate increased from 1550 s-1 to 2990 s-1, the yield stress of (Cu0.47Zr0.45Al0.08)98Dy2 BMG first decreased from 1508 MPa to 1404 MPa, and then increased to 1593 MPa. The fracture behaviors of (Cu0.47Zr0.45Al0.08)98Dy2 BMG were studied by using scanning electron microscopy to examine the fracture surface. Fracture occurred in the pure shear mode with strain rates below 2100 s-1, whereas shear fracture and normal fracture occurred simultaneously under strain rates of 2650 s-1 and 2990 s-1.
RESUMO
3-Nitro-1,2,4-triazol-5-one (NTO) rubidium and cesium complexes were synthesized by mixing the aqueous solution of NTO and their respective metal carbonates. Their thermal decomposition and the non-isothermal kinetics of the dehydration reaction were studied under the non-isothermal condition by DSC and TG-DTG methods. The kinetic parameters were obtained from analysis of the DSC and TG-DTG curves by Kissinger method, Ozawa method, the differential method and the integral method. The most probable mechanism functions for the dehydration reaction of the title complexes were suggested by comparing the kinetic parameters. The dehydration decomposition reaction of RbNTO.H2O and CsNTO.H2O appears to be the same as Avrami-Erofeev equation: f(alpha) = (5/2)(1-alpha)[-ln(1-alpha)](3/5), G(alpha)=[-ln(1-alpha)](2/5), n = 2/5. The critical temperature of thermal explosion is 240.88 degrees C for RbNTO.H2O and 246.27 degrees C for CsNTO.H2O.
