Improved mechanical properties by high-energy milling and Spark Plasma Sintering of a TRIP-matrix composite

Abstract

A composite reinforced with 5 vol% MgO partially stabilized zirconia and a high-alloyed TRIP-steel matrix (16% Cr, 6% Ni, 6% Mn) was processed. The objective was to trigger a phase transformation under mechanical stresses within the steel and the ceramic. Therefore, the composite was processed by both mixing (110 r/min) and dispersing by intense milling (250 r/min) of the initial powders, and subsequent Spark Plasma Sintering. During Spark Plasma Sintering, the dwell time was varied (5 min, 10 min). The steel/MgO partially stabilized zirconia interfaces were improved through the intense milling and the 10 min dwell time. Furthermore, 50% of the MgO partially stabilized zirconia transformed to the monoclinic phase under quasi-static compressive loading (10−3 s−1) and the composite had a 1% offset compressive yield strength of 665 MPa. Independent from the processing route, 65% of the steel transformed to α′-martensite.