Caracterização de ligas Fe-Ni processadas por metalurgia do pó: influência dos parâmetros nas propriedades mecânicas

Abstract

Powder metallurgy becomes an important process for obtaining pieces with complex geometry, making them increasingly viable. The aim of this work is to characterize and evaluate the influence of mixing energy and mixing time on the microstructure and mechanical properties (hardness) of the alloy Fe 70% - 30% Ni, used in electronics and structural materials of automotive engine parts, being produced by powder metallurgy (PM). The Fe-Ni alloys were mixed at low and high energy, 25 and 200 rpm, respectively, for 2 and 4 hours, uniaxially cold compacted with compaction pressure of 8 tons and sintered at 1,100°C. Simulations to predict the phases present were performed using thermodynamic simulation by the software Thermo-Calc, which showed the possible existence of CCC and CFC phases. The microstructure was evaluated by Scanning Electron Microscopy (SEM), enabling visualization of the amount and size of pores, as well as shape and size of the grains. Energy dispersive spectroscopy (EDS) for chemical mapping punctual and chemical analyzes was used.