TEMPERING BEHAVIOR OF MARTENSITIC COPPER-ALUMINUM ALLOYS

Cu-Al alloys with 10 to 13. 5% Al, homogenized at 900 or 1000 C and quenched in ice water, were tempered at 250 to 550 C in salt baths. Phase transformations were determined by electron and optical microscopy. Five different tempering mechanisms are distinguished in defined temperature and composition ranges. These are plotted in the equilibrium diagram, shown schematically, and discussed in detail. For a Cu-10. 59Al alloy tempered structures are correlated with previously determined tensile properties.