Papers by Keyword: Solidification Mechanism

Abstract: The microstructure of an Al-Ti-C-Ce alloy was studied by XRD, SEM, and EDS. This mother alloy consisted of α (Al),(AlTi),(TiC), and (Ti₂Al₂₀Ce) phases, and there was a second phase of a composite structure in the alloy. The TiC phase was the primary crystal nucleus, and the (TiAl) phase was segregated on the surface of TiC phase to form a TiC-(TiAl) composite crystal nucleus. Al formed a fine TiC-(TiAl)-α (Al) primary composite crystal nucleus by a peritectic reaction.The primary composite crystal nucleus with higher energy and larger cluster size was taken as the core,and other composite crystal nuclei were segregated on its surface to form a secondary composite crystal nucleus. Next, the secondary composite crystal nucleus formed the tertiary composite crystal nucleus, and so on, to form the titanium-enriched area of composite particles.

Abstract: Twin roll casting (TRC) has been demonstrated to be a process capable of producing Mg sheets at a significantly reduced cost. However, the quality of the Mg sheets produced by the TRC process is limited due to the formation of coarse columnar grains and severe centreline segregation, which reduces both the strength and ductility of Mg-alloys. In this paper, melt conditioned (MC) has been employed prior to twin roll casting (TRC) of AZ31 alloy to understand its effect on the solidification mechanism. For comparison, AZ31 alloy strips were also produced through conventional TRC process. The results showed that the solidification mechanism can be completely altered by introducing MC in TRC process.