Al–Al7Cr eutectic in Al–Cr alloys synthesized by laser alloying

Al–Cr surface alloys prepared by injecting Cr powder into the melt pool generated in an Al substrate by a high-powered CO2 laser beam followed by laser remelting present a microstructure consisting of equiaxed cells comprised of extremely fine Al7Cr particles radially distributed in an α-Al matrix. The analysis of this microstructure shows that it originated from solidification. Its morphology is typically eutectic, confirming the existence of the L → α-Al + Al7Cr eutectic reaction predicted by some Al–Cr phase diagram configurations proposed recently.