A NEW AND SIMPLE PROCESSING (MEETING) APPROACH FOR THE DEVELOPMENT OF STRUCKTUALLY ATTRACTIVE, CHEAP,LOWERDENSITY (-3.7G/CM) HIGH TEMPARETURE INTERMETALIC COMPOSITE

摘要

The present high temperature materials have imitations for reasons that are very well known. Some of them are difficult to make, high density, expensive, very high temperature is needed to make them and the properties that are obtained do not often give what is needed due to inhomogeneity of the phases and their associated properties problem such as creep-fatigue properties, oxidation resistance and many others. In this patent application, the development of intermetalic alloy is based on the first principle of materials engineering. Here, the Al3Ti (non deforming phase) (density=3.39 g/cm3) in its ellipsoids form acts as high temperature reinforcing phase and the matrix Al5CuTi2 (density=4 g/cm3) acts as the facile phase which is essential for strain accommodation. Here just like the other moderate temperature Al-Ti alloy (applied for patent), Al3Ti locks the grain boundary movement by occupying a substantial portion of grain boundary area. Therefore the developed alloy would have excellent inherent high temperature stability. This with Al5CuTi2 as matrix phase would in principle meet most of the high temperature structural properties requirements such as excellent oxidation resistance thermal stability at the service temperature, long stress rupture life (creep resistant) and excellent high cycle fatigue, the matrix's cleanliness would aid in achieving the aforementioned properties. The idea here stems from the facts (gathered from prior literature study) that showed the matrix is very stable to very high temperature (maintains 500 MPa yield strength up to about 600ºC). The matrix has also some room temperature ductility due to its L12 (fcc) crystal structure. Although, some of them need to be verified using experimental facts but the common sense of the present alloy design approach justifies enough efficacy for a grant of patent