Carbide

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

Boron carbide-reinforced alumnium 1100 matrix composites: Fabrication and properties

Abstract: With the increasing trend in the use of light-weight functional material in emerging industrial applications, understanding the fabrication of aluminum–boron carbide (ABC) composite is becoming needful. In this context ABC composites up to 25 wt.% boron carbide (B 4 C) particulate reinforcement in alumnium 1100 matrix were prepared at 873 K and the resulting microstructure and physico-mechanical properties were studied. Dark-field images showed the continued existence of porosities. The density and electrical conductivity decreased from 2.52% to 1.8% and from 48% to 11% of the International Annealed Copper Standard, respectively. There was an 11-fold increase in hardness with 25 wt.% B 4 C addition. Although the flexure strength of the composite decreased because of transition in formation of phases at grain boundaries from ternary Al–B–C to binary Al–B, growth of Al–B and retention of boron carbides, the flexure modulus showed up to 8 times improvement with increased fraction of reinforcement. Fractographs revealed extensive damage to grain boundaries because of generated shear and particle pull-out. The tendency for brittle fracture increased with higher reinforcement fractions. The study forms the basis to commercialise ABC composites for required applications, and it is concluded that even though uncoated boroncarbide reinforcements embrittle the aluminum matrix in as-reinforced condition, improvement in other as discussed properties is significant. The study also indicates that the ductility of the metal matrix composite (MMC) may be improved by increasing the interfacial bonding and decreasing the overall porosity contents of the composite.

Precipitation of carbides at γ─α boundaries in alloy steels

Abstract: Austenite containing 1 to 2 wt% vanadium and 0.2 wt% carbon, held in the range 600 to 850 degrees C transforms to an extremely fine dispersion of V$\_{4}$C$\_{3}$ in ferrite. The carbide particles are nucleated on the $\gamma $-$\alpha $ phase boundary at successive positions during the transformation, forming sheets of precipitate which are 5 to 30 nm apart, while the individual particles are 3 to 10 nm diameter (interphase precipitation). High resolution electron microscopy has provided details of the morphology and crystallography of the carbide particles and the transformation front. A similar reaction has been studied in an iron +6.3wt% tungsten +0.23wt% carbon alloy in which M$_{6}$C precipitates on a much coarser scale enabling precise observations to be made on the transformation front. Interphase precipitation has also been examined in an iron +3.45 wt% molybdenum +0.22 wt% carbon alloy. A model is proposed for the interphase precipitation which takes into account the observed morphology and crystallography of the carbide phases and of the ferrite.

Room‐Temperature Carbide‐Derived Carbon Synthesis by Electrochemical Etching of MAX Phases

Abstract: Porous carbons are widely used in energy storage and gas separation applications, but their synthesis always involves high temperatures. Herein we electrochemically selectively extract, at ambient ...