Rapid solidification characteristics in melt spinning a Ni-base superalloy

Effects of Zr on microstructure and mechanical properties of Al-Cu base ribbons spun by planar flow casting

“…Similar phenomenon of the transition behavior was observed for the FeA1 ribbons containing small amount of ZrB2 by Morris et al [10]. 2(a) shows the A1-4.3 wt.% Cu ribbon exhibiting the heterogeneous microstructurai distribution which is considered to be caused by the local contact behavior [8]. Polygonal equi-axed grains with linear edges nucleated at the high-contact region, whereas multiple band-type structures appeared parallel to the wheel rotation direction at the non-contact region.…”

“…It is also noted that the thickness ratio of the columnar structure to the entire thickness of the ribbon decreased as Zr content increased from 0.1 wt.% to 0.5 wt.%. The columnar layer has been reported to consist of partitionless solidification structure owing to the very rapid heat extraction during ribbon fmmation [1,4,8]. From this microstructural observation, it can be suggested that the addition of Zr accelerates the destabilization of the planar front structure, causing the morphological breakdown to the cellular/dendritic st:ructure approximately from the lower central region of tlhe wheel-side surface.…”

“…A series of studies has suggested that the local solidification velocity and the resultant multi-layered structures through the ribbon thickness are closely related not only to material characteristics, but also to process parameters [3][4][5][6]. The multi-layered structures of the ribbon stem from the microstructural transition corresponding to the absolute stability criterion in rapid solidification regime [7,8]. The stability criterion for the planar front morphology is expected to be altered by the presence of a third element in the binary alloy system.…”

Structural and Electrical Properties Characterization of Sb1.52Bi0.48Te3.0 Melt-Spun Ribbons

“…This yields an average residence time of roughly 30 µs. As shown by Huang et al [51], τ is correlated to the ribbon thickness R, such that R ≈ τ 1/2 ×10 −3 m s −1/2 . Taking into account the above-mentioned value of τ, the thickness of the ribbons should be ~5 µm, that is close to the experimental values obtained by SEM.…”

Corrosion and tarnishing characteristics of low gold content dental casting alloys

“…In our tests with low gold content dental casting alloys, we used a twin-roll, rapid solidification apparatus (illustrated), which is capable of cooling rates up to 1 000 000°C/s and normally produces RSR material in the form of 0.1 to 0.2 mm thick ribbons. In conventional melt-spinning RSR practice, the metallic ribbons produced often exhibit differential cold-face and hot-face microstructures [32,33], caused by cooling rate differences through the thickness of the strip. The side of the ribbon in contact with the wheel (cold face) solidifies faster than the outer face which can lead to a variety of microstructures across the strip thickness.…”