The Feasibility of Estimating Elastic-Plastic Strain in Powder Structural Steel with Different Residual Porosity by Magnetic Methods
The world’s output of products made of sintered powders is constantly growing due to high productivity and efficiency of powder metallurgy processe s. Safe operation of machine parts and structural components made of sintered powder ma t ials calls for reliable methods of nondestructive testing. The paper presents a procedure of t wo-parameter testing of product structure and porosity, as well as results of investigatio ns into the effect of tensile stresses on the magnetic characteristics of powder structural stee with different residual porosity; it also discusses the applicability of the results for estimat ing elastic-plastic strains.
Correlation between the stress-strain state parameters and magnetic characteristics of carbon steels
A method for reconstruction of the stress-strain diagrams of steel objects from their magnetic characteristics determined directly during tension has been suggested. The coercive force, residual induction in the major hysteresis loops, and the maximum magnetic permeability are recommended as parameters for nondestructive testing of stresses and strains.
Phase characterisation of simulated high burn-up UO2 fuel
Abstract To determine the lattice constant variation with burn-up and the oxidation behaviour at high temperatures, simulated UO2-spent fuels with burn-ups up to 200 GWd tM−1 were prepared by cold pressing and sintering and characterised by X-ray diffraction analysis and thermogravimetry. The fcc-lattice parameter of the sintered samples determined at room temperature, showed a continuous decrease with the simulated burn-up. During oxidation the conversion of the simulated fuels to the (U,FP)4O9 and (U,FP)3O8-type phases was strongly delayed when the simulated burn-up exceeded 80 GWd tM−1. Also, at high burn-ups (>100 GWd tM−1), large fractions of the (U,FP)4O9-type phase remained untransformed to (U,FP)3O8 after prolonged exposure to air at 950–1000°C. This suggests a marked widening of the (U,FP)4O9-phase field when the amount of substituted uranium atoms exceeds values of about 8%.