摘要：A novel method for testing stress–strain curves of non-metallic materials was *** high temperature stress-strain curves of MnS were preliminarily obtained and corrected to account for the influence of *** the finite element method,the influence of deformation parameters on the deformation evolution of MnS inclusions was investigated based on the experimental reference *** corresponding physical experiment was designed for comparative *** results indicate that the experimental high-temperature deformation data of MnS are highly *** the process of matrix deformation,the shapes of MnS inclusions change from spherical to ellipsoidal and even to *** are some differences in the morphological deformation of MnS inclusions located at different *** the increase in the initial size of MnS inclusions,the risk of failing the inclusion-flaw inspection increases and the forging quality further deteriorates.

摘要：The forming performance of sheet metals in the deep-drawing process with ultrasonic vibrations can be improved by the surface effect between the sheet metal and the die.A sheet metal friction test with ultrasonic vibrations is performed to explore the cause of the surface *** frictional characteristics are investigated,and the corresponding friction expressions are established based on the contact mechanics and the elastic–plastic contact model for rough *** is caused by the elastic–plastic deformation of contacting asperities under normal *** actual contacting region between two surfaces increases with normal loads,whereas the normal distance *** normal distance between the contacting surfaces is changed,asperities generate a tangential deformation with ultrasonic vibrations,and the friction coefficient is eventually *** vibrations are applied on a 40Cr steel punch at the frequency of 20 kHz and the amplitude of 4.2μ*** the friction tests,the punch is perpendicular to the surface of the magnesium alloy AZ31B sheet metals and is sliding with a relative velocity of 1 mm/*** test results show that the friction coefficient is decreased by approximately 40%and the theoretical values are in accordance with the test values;Ultrasonic vibrations can clearly reduce wear and improve the surface quality of parts.