The combined influence of both melt filtration and cooling rate on the microstructure features and mechanical properties of A356 cast alloy was studied. A step casting model with five different thicknesses was used to obtain different cooling rates. The effect of melt filtration was studied by using of 10 and 20 ppi ceramic foam filters in the runner. Results showed that secondary dendrite arm ...

An online numerical simulation is presented that is capable of predicting state variables such as flow rate, melt temperature, shear rate, and melt viscosity by using real time data from a nozzle pressure sensor. The simulation solves the non-Newtonian nonisothermal polymer flow into multicavity tools while executing rapidly enough for real time process control. Numerical accuracy and stability...

Chemical differentiation of rocky planets occurs by melt segregation away from the region of melting. The mechanics of this process, however, are complex and incompletely understood. In partially molten rocks undergoing shear deformation, melt pockets between grains align coherently in the stress field; it has been hypothesized that this anisotropy in microstructure creates an anisotropy in the...

The effects of filler content and its surface treatment with silane coupling agent on the melt shear viscosity of glass bead-filled polypropylene (PP) composites have been investigated using a capillary rheometer at a wide shear rate scope of 150 to 7200 s and temperature range of 160 to 200 C. The melt flow obeys power law, but the slopes of the flow curves have transitions at the shear rate o...

[1] Global observations of mid-ocean ridge (MOR) bathymetry demonstrate an asymmetry in axial depth across ridge offsets that is correlated with the direction of ridge migration. Motivated by these observations, we have developed two-dimensional numerical models of asthenospheric flow and melting beneath a migrating MOR. The modification of the flow pattern produced by ridge migration leads to ...

The expansion of molten aluminum foam was studied to determine flow mechanisms in the cellular melt. The structure of the foaming melt evolved through a series of deformation stages before the foam stabilized and solidified. Changes in cell geometry during foam expansion were observed at different positions within the mold cavity and analyzed to determine flow mechanisms. The deformation patter...

A concept for the casting of metallic fuels pins containing low vapor pressure materials is presented and discussed. The important physics of this concept include the mass transport of americium from the melt, the induction heating and stirring of the melt, plus the casting of long slender fuel rods. This paper discusses and presents preliminary modeling results for the casting of long, slender...

As is well known, the extrusion rate of polymers from a cylindrical tube or slit (a "die") is in practice limited by the appearance of "melt fracture" instabilities which give rise to unwanted distortions or even fracture of the extrudate. We present the results of a weakly nonlinear analysis which gives evidence for an intrinsic generic route to melt fracture via a weakly nonlinear subcritical...

The present invention is directed to a method for powder coating a metal substrate using a low-melt polyamic acid (PAA) polymer that readily imidizes to polyimides. These low-melt PAAs have been shown to be useful in resins applied as powder coatings to metal surfaces. The resin includes an end-capping material capable of providing crosslinking functionality to at least one end of the low-melt ...