| Al-10wt% Ti alloy has been produced by mechanical alloying (high energy ball milling) and subsequent hot extrusion. By means of thermal analysis of mechanically alloyed powder and X-ray analysis of sintered specimen, it has been found that Al₃Ti was formed at 260℃ during the degassing process. The fact that Al₃Ti was thermally stable was obtained from the results of TEM, SEM, X-ray, hardness test of as-extruded specimens which are exposured at various time (1-40hr.) and temperature (300 ℃, 400℃, 500℃). This was conincided with low solubility and diffusivity of Ti in Al matrix. Room temperature and high temperature (300℃, 500℃) tensile strengths of mechanically alloyed Al-10wt% Ti alloy were superior to those of conventional precipitation-hardened alloy (2014-T6 and 2219-T81). This improvement of tensile strength was due to homogeniously and finely dispersed Al₃Ti, oxide and carbide With increasing Ti and PCA contents, tensile strength increased while ductility decreased. Oxide and carbide revealed stronger effects on high temperature strenght than those of Al₃Ti. High temperature properties unchanged after heat treatment. |
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