ELASTIC PROPERTIES AND STRUCTURAL OBSERVATIONS OF DISTALOY SA POWDER SINTERED WITH BORON AND CARBON

Abstract

One of the methods aimed at increasing the density in PM parts is the process of activated sintering performed by adding boron as elementary boron powder, for example. Under this researchwork novel, PM materials were obtained based on prealloyed and diffusion bonded powder (type: Distaloy SA) with the following chemical composition: Fe-1.75%Ni-1.5%Cu-0.5%Mo, with the addition of 0.55 wt.% carbon and boron (0.2, 0.4 and 0.6 wt.%). Distaloy SA samples alloyed with carbon and boron were manufactured by mixing the powders in a Turbula mixer, then compacting the mixture in a hydraulic press under a pressure of 600 MPa and sintered in a tube furnace at 1473 K for 60 minutes in a hydrogen atmosphere. The densification process of Distaloy SA parts with boron and carbon depends on the sintering mechanism. In order to evaluate the sintering mechanism of the PM samples, structural investigations using SEM/EDS were performed. During sintering of these materials at 1473 K, a liquid phase is generated as a result of the reaction occurring between the alloy matrix and the complex of carbo-borides, which leads to a considerable degree of consolidation. The elastic properties of the sintered samples (such as Young’s modulus and the damping coefficient) were measured in a tensile test with a Förster elastometer.