EFFECT OF MICROSTRUCTURE AND COOLING RATE ON THE MECHANICAL PROPERTIES OF TI-6AL-6V-2SN.
ARMY MATERIALS RESEARCH AGENCY WATERTOWN MASS
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The investigation concerns the separate effects of microstructure and cooling rate on the mechanical properties of the titanium alloy 6Al-6V-2Sn. Microstructure was varied by forging a 6-inch-diameter bar to diameters of 4-, 2-, and 58-inch. Each bar was then tested in both the annealed and heat-treated conditions. The effect of cooling rate alone was obtained by trepanning sections of 4-, 2-, and 58-inch diameter from the 6-inch-diameter bar, heat treating and testing. Mechanical property data were obtained utilizing tensile and impact specimens which were machined from the bar or section diameters following the final treatment phase. Photomicrographs are shown for a typical area of each conditions. Results of the investigation show that working tends to refine the overall microstructure, whereas cooling rate is a determining factor on the structure of the matrix but has little or no effect on the primary alpha size. Both microstructure and cooling rate strongly influence the resultant mechanical properties of this alloy. Primary microstructure is the major contributing factor on ductility and impact while both primary microstructure and cooling rate influence the final strength properties. Author