A. Muthuchamy

Microstructural Evolution of Iron Based Alloys Produced by Spark Plasma Sintering Method

The effect of alloying additions, such as copper, carbon, and molybdenum with carbonyl iron powder, on the densification behavior, microstructural evolution, and mechanical properties of spark plasma sintered (SPS) compacts have been investigated in this work. The sintering temperature, pressure, and time during SPS were 1120°C, 30 MPa, and 5 min, respectively. Fe–2Cu–0.8C–0.6Mo was found to exhibit the highest density, hardness, and also tensile strength among all the compositions attempted. The microstructural examination of fractured surfaces of the sintered samples revealed the evidence of a mixed mode of fracture in all the alloy compositions.

Effect of TiC Addition and Heating Mode on the Electrochemical Response of Powder Metallurgy Processed Corrosion-Resistant Austenitic and Ferritic Steels

Austenitic steel 316L and ferritic steel 434L produced by sintering of atomized powders with additions of different volume fractions (0, 4, 8, and 12 vol.%) of titanium carbide particles in microwave and conventional furnaces are studied. The microwave heating results in more intense densification, hardening, higher corrosion resistance, and grain refinement as compared to sintering in the conventional furnace. Steel 316L with 4 vol.% TiC sintered in the microwave furnace exhibits the highest corrosion resistance.

Influence of sintering temperature on mechanical properties of spark plasma sintered pre-alloyed Ti-6Al-4 V powder

Abstract Spark plasma sintering provides faster heating that can create fully, or near fully, dense samples without significant grain growth. In this study, pre-alloyed Ti-6Al-4 V powder compact samples produced through field assisted sintering in a spark plasma sintering machine are compared as a function of consolidation temperature. The effect of sintering temperature on the densification mechanism, microstructural evolution and mechanical properties of spark plasma sintered Ti-6Al-4 V alloy compacts was investigated in detail. The compact, sintered at 1100 °C, exhibited near net density, highest hardness and strength as compared to the other compacts processed at a temperature lower than 1100 °C.

Mechanical and Electrochemical Characterization of Super-Solidus Sintered Austenitic Stainless Steel (316L)

Abstract The present study compares the mechanical and electrochemical behaviour of austenitic (AISI 316L) stainless steel compacted at various pressures (200, 400 and 600 MPa) and conventionally sintered at super-solidus temperature of 1,400°C. The electrochemical behaviour was investigated in 0.1 N H2SO4 solution by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The shrinkage decreased and densification has been increased with increasing pressure. The mechanical and electrochemical behaviour with pressure has been correlated with densification response and microstructure (pore type, volume and morphology). Highest densification (~92% theoretical) achieved at 600 MPa (compaction pressure) and 1,400°C (sintering temperature) resulted in excellent combination of tensile strength and ductility (456 ± 40 MPa, 25 ± 1.1%), while showing excellent corrosion resistance (0.1 mmpy or 4.7 mpy).