Effectively enhanced strength by interfacial reactions in in-situ carbon reinforced Al matrix composites

Abstract This work presented an in-situ method to synthesize carbon on commercial micro-Al powders. The modified Al powders were obtained in a furnace in a simple way by degreasing the PVB on the Al surface, which previously introducing to the Al particles in an alcoholic environment. The modified carbon coating Al powders were used to consolidate the carbon-reinforced Al matrix composites (Al/C composites) by a powder metallurgy approach with hot pressing under different temperature. Under relatively low temperature, the carbon was distributed around the Al particles in the Al/C composite, then the carbon tended to aggregate on the particle surface, finally, the carbon reacted to Al to form Al4C3 phase distributing within the Al matrix. The sintering mechanism of Al/C composites was illustrated and combined with the microstructure observed by TEM. The ultimate tensile strength and elongation of the Al/C composite enhanced by carbon sintered under 630 °C were 304.82 MPa and 20%, respectively. The strengthening efficiency of the Al/C composites reached a high R of 74. The strengthening effect was mainly attributed to the dislocation strengthening, Hall-Petch, and solid solution strengthening mechanisms.