Effect of Aging Temperature on the Microstructure, Local Mechanical Properties, and Wear Behavior of a UNS S32750 Super Duplex Stainless Steel

摘要

In this paper, the effect of aging temperature on the microstructure, local mechanical properties and wear behavior of a UNS S32750 super duplex stainless steel is investigated. A massive preferential precipitation of sigma phase and Cr2N is detected at the periphery of ferrite with an increase in their extent as aging temperature increases. Simultaneously, the delta phase decomposition is accentuated with temperature and reaches its maximum at 850 degrees C. This behavior results in an enhancement in hardness and Young's modulus accompanied by a higher plasticity ratio. The wear resistance of the aged samples is investigated in terms of friction coefficients and wear rates against two counterparts. The wear performance follows sigma phase presence, the higher sigma phase extent, the higher the wear resistance. It is found that the change in wear mechanisms in the 850 degrees C aged samples from abrasive against AISI-304L counterpart to adhesive-oxidative against Al2O3 counterpart is responsible in the increase in wear resistance.