THE DEVELOPMENT OP STRONG TOUGH TITANIUM ALLOYS for Ordnance Use

摘要

The initial stages of this investigation consists of the preparation and evaluation of two series of 15# bottom-pour, skull, are melted ingots, having the base composition of either Ti-7Mn or Ti-5Al-2.5Sn together with small singular or combined a dditions of the contaminants. Based on results from the above work, two larger cold mold ingots, one all-alpha, the other combined alpha-beta, were then cast of the mast promising composition and evaluated, utilizing those heat treatment cycles which had resulted in the more favorable strength-toughness rela¬tionships, In general, the alpha-alloy proved to be more tolerant of the contaminants than did the alpha-beta alloys, even though the effects were greater in some respects. Strength levels showed a greater increase, per unit of contaminant, for the alpha alloys than for the alpha-beta ones, but tensile ductility losses, on the other hand, were less, and not as erratic Toughness, as measured by impart tests, suffered greater damage by addition of contaminants to the alpha ingots, but the initial level of impact was so much higher that the alphas still retaimed approximately twice theimpact resistance of the alpha-betas. Through variations in heat treatment, a wide range of strength levels may be produced in the latter alloy, but toughness, for a given composition, remained quite constant. The following trends and/or effects were observed.