Processing of AISI M2 high speed steel reinforced with vanadium carbide by solar sintering

This investigation addresses sintering of AISI M2 high speed steel reinforced with vanadium carbide (VC) using concentrated solar energy (CSE). CSE allows significant reduction of processing times due to its enhanced activating effect and high heating rates achieved. The M2 steel powders were reinforced with 3, 6 and 10 wt% VC and sintered under a N2–5%H2 atmosphere at two solar installations: a Fresnel lens (FL) and a solar furnace (SF). The microstructures of the solar-sintered samples were studied and compared with other samples sintered using a conventional tubular furnace. Results show that the use of solar installations significantly reduces optimal sintering temperatures in more than 200 °C. Furthermore, the use of CSE allows a dramatic reduction of the treatment times from cycles longer than 10 h in tubular furnace (TF) to cycles of 15 min in solar furnace. Finally, the addition of VC increases hardness in most of the studied cases but in the samples processed in the solar installation the increase is higher achieving 987 HV in the sample reinforced with 10 wt% of VC without any additional thermal treatment. The microstructural analysis together with X-ray diffraction characterization allows explaining these results.