Minority carrier lifetimes were measured to determine the effect of phosphorus gettering on cast multicrystalline silicon substrates from central and end regions of two different ingots. One ingot exhibited visibly inferior crystallographic structure, and consistently showed lower lifetimes. For the low quality ingot, wafers from the bottom region did not respond to gettering, whilst those from...

It is nowadays generally accepted that controlling the tapping temperature of steel by immersion pyrometry is an important means of improving steel quality. Broadly speaking, if the steel is too hot when tapped the ingots tend to crack, and if too cool they tend to suffer from “shell” on the surface and non-metallic inclusions beneath. From this point of view it is now simply a question of esta...

The structural evolution and segregation in a dual alloy made by electroslag remelting (ESR) was investigated by various analytical techniques. The results show that the macrostructure of the ingot consists of two crystallization structures: one is a quite narrow, fine, equiaxed grain region at the edge and the other is a columnar grain region, which plays a leading role. The typical columnar s...

G. W. Ao, M. G. Shen, Z. S. Zhang, B. L. Li: College of Materials and Metallurgy, University of Science and Technology Liaoning, Anshan City, China Hollow side wall insulation mathematical model of unidirectional solidification temperature field was carried out. With the aid of finite element analysis software ProCAST, directionally solidified ingot temperature field with hollow lateral wall in...

Free-moving “floating” grains have been linked to macrosegregation in direct-chill (DC) aluminum castings. The presence of these grains in the sump of a solidifying ingot has been acknowledged based on measurements of cast microstructures and by recent work using a turbulent jet to suspend solute-poor grains and minimize macrosegregation. Experiments in this study were designed to sample grains...

Macrosegregation in direct chill (DC) continuous casting of an Al-4.5 wt pct Cu round ingot is numerically simulated. The model incorporates descriptions of heat transfer, solute redistribution, and melt convection on the system scale with microscopic relations for grain growth, solutal undercooling, and microsegregation. Simulations are conducted to study the effects of mushy zone permeability...

The present state of melting techniques for IN7 18 and IN625 has well-defined limitations both in terms of the ingot structure and maximum ingot size which is fabricable by the various processes. Although there are methods already in industrial use which would extend both of these limits, since the alloys must be produced at a relatively low cost here are further limitations on the practical ma...

Present chemical-physical characteristics of ingot and continuous casting powders can be critically evaluated pointing out history of invention of these materials. In an original tone, pioneering nature of first developments of casting powders will be described, illustrating empirical know-how of casting powders technology, based on trial-and-error method. It will be originally emphasized that ...

segregates. Although good agreement with experiments was MACROSEGREGATION in large steel ingots is one achieved, the model relied on many approximations (such of the most well-known and now classical problems in the as estimating the flow velocities). It should also be menfield of solidification and casting.[1] It arises from the relative tioned that many models have appeared in the literature ...

A valuable characteristic of the "IPS Empress" used for producing all ceramic dental restorations is that it is a prefired ceramic ingot. The ingot is heated, softened and press-injected into the cavity, and ceramic restorations are fabricated by the lost wax casting method. The leucite crystal present in the ingot are scattered and distributed into the glassy phase in a more homogeneous manner...