The Research On Process Of Al-Ti-C Master Alloy Prepared By Thermal Explosion Method

Al-Ti-C master alloys have been prepared by thermal explosion mode of self-propagating high-temperature synthesis (SHS ) using Al,Ti and C powder. In this paper, some influence factors on the synthesis technics of Al-Ti-C master alloys have been researched ,such as reaction temperature, heat preservation time, component, powder size. XRD, OM, SEM, EDS, MEF3 were used to analyse microstructure and grain refining of Al-Ti-C master alloys. At the same time, Refining capability of the Al-Ti-C master alloys has been compared with that of Al-Ti-B master alloys made in LSM, and fading performance of Al-Ti-C master alloys has also been researched.Experimental results show that reaction temperature and heat preservation time have obviously influenced the microstructure and refining performance of Al-Ti-C master alloys. Because Al, Ti, and C powder do not react completely in 740 ℃, extricating Ti still exists in the Al-Ti-C master alloys, and the refining effect is bad. With the increase of temperature, the reaction is more complete. But in 900 ℃, banding or flaky TiAl₃ has been fond in the Al-Ti-C master alloys, and refining effect reduced sharply. Therefore, it is optimal technology that reaction temperature is 780℃ and insulation time is 6 minutes.With the changes of Al content, excessive or insufficient Al content has all resulted in the appearance of extricating Ti. In addition, excessive Ti content has also resulted in the appearance of extricating Ti and banding or flaky TiAl₃ in the Al-Ti-C master alloys. With the changes of powder size, C powder size has influenced greatly the microstructure and refining performance of Al-Ti-C master alloys, but the influence of Ti powder size is slight. The microstructure and refining effect of Al-Ti-C master alloys are good when compounding is 5:2:1, C powder size is + 1300 — 1100 mesh and Ti powder size is + 540 —460 mesh.