Carbide

About: Carbide is a research topic. Over the lifetime, 36331 publications have been published within this topic receiving 503586 citations.

The tempering of iron- carbon martensite; dilatometric and calorimetric analysis

Abstract: The aging behavior of iron-carbon martensite (1.13 wt Pct C) between -190 °C and 450 °C was investigated by quantitative analysis of the corresponding changes in volume and enthalpy. A method to determine activation energies of the occurring solid-state transformations by performing non-isothermal measurements of some physical property of the specimen has been described. Martensitic specimens were prepared by carburizing pure iron and quenching in brine and liquid nitrogen. The dilatometric and calorimetric experiments were supplemented with microhardness measurements. At least five different stages of structural change can be distinguished, which are quantitatively analyzed in terms of their effects on volume and enthalpy: (i) transformation of retained austenite into martensite (between −180 and −100 °C); (ii) redistribution of carbon atoms (below 100 °C); (iii) precipitation of transition carbide (between 80 and 200 °C); (iv) decomposition of retained austenite (between 240 and 320 °C); and (v) conversion of transition carbide into cementite (between 260 and 350 °C).

Effect of machining parameters on surface roughness and tool wear for 7075 Al alloy SiC composite

Abstract: In the present study, an attempt has been made to investigate the influence of cutting speed, depth of cut, and feed rate on surface roughness during machining of 7075 Al alloy and 10 wt.% SiC particulate metal-matrix composites. The experiments were conducted on a CNC Turning Machine using tungsten carbide and polycrystalline diamond (PCD) inserts. Surface roughness of 7075Al alloy with 10 wt.% SiC composite during machining by tungsten carbide tool was found to be lower in the feed range of 0.1 to 0.3 mm/rev and depth of cut (DOC) range of 0.5 to 1.5 mm as compared to surface roughness at other process parameters considered. Above cutting speed of 220 m/min surface roughness of SiC composite during machining by PCD tool was less as compared to surface roughness at other values of cutting speed considered. Wear of tungsten carbide and PCD inserts was analyzed using a metallurgical microscope and scanning electron microscope. Flanks wear of carbide tool increased by a factor of 2.4 with the increase of cutting speed from 180 to 240 m/min at a feed of 0.1 mm/rev and a DOC of 0.5 mm. On the other hand, flanks wear of PCD insert increased by only a factor of 1.3 with the increase of cutting speed from 180 to 240 m/min at feed of 0.1 mm/rev and DOC 0.5 mm.