Abstract
In tradition, the development of an alloy system is almost based on a principal element. The study of equal-mole alloy is expected for providing an entirely different approach to break the conventional constraint so that we might have more freedom to design alloys. Moreover, the equal-mole alloy system is proposed exhibiting higher glass-forming tendency due to the strain energy in the atomic arrangements, which arises from the different atomic size. In the present study, cooling rate and constituent elements, and atomic size difference were varied to understand their effets on microstructure and glass forming ability. The results show in general that microstructures of the as-stamped foil contain primary dendrite and matrix phases. The primary crystalline dendrite phase of the 6-component alloy is composed of Ti atoms and that of the 7-and 8-component alloy is composed of Ti and Al atoms. Unlike the one simple matrix phase in 6-component alloy, the matrix phase in 7-, 8-component alloys consists of dendrite and interdendrite phases. The matrix phase in 6-component alloy and the interdendrite matrix phase in 7-and 8-componet alloy in as-stamped condition has been identified as a BCC structure by XRD and TEM investigations. The BCC preferable to FCC and HCP is attributive to the more open structure of BCC phases, which could relax the lattice distortion and effectively lower the free energy of the system. The dendritic matrix phase in 7-and 8-component alloys is amorphous. For 6-component alloy, an amorphous matrix phase could only be formed in this study by melt spinning. For alloys with increasing number of components, larger atomic size difference and higher cooling rate could enhance the glass forming ability. The hardness of the 5 to 8 component alloys is related to the number of the constituent elements. It manif0ests a maximum value of about Hv 1049 for as-stamped 6-component alloy.