Component Shape Retention in Liquid Phase Sintering of Prealloyed Powders

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9610280 German New research on supersolidus liquid phase sintering (SLPS) addresses three topics. The first examines microstructural evolution during heating and sintering. A current model of the process makes assumptions on the rate of grain growth, liquid film thickness, shrinkage rate, semisolid particle viscosity, and causes of distortion. These assumptions are addressed by experimentation performed on model systems using microstructure measurements from quenched samples and in situ testing. The goal is to increase the model reality and to recognize any behavior between systems. The second topic is the prediction of final component size and shape. A computational prediction for the loss of structural rigidity as liquid spreads on the grain boundaries needs verification. Furthermore, gradients in grain size, particle size, packing density, substrate friction, and heat transfer need to be included in the final component size and shape predictions. The third activity extends the model to several other processing conditions (bimodal-sized powders, powders of differing compositions, high viscosity systems, reactive systems). %%% Success in this research should positively impact the use of the SLPS process to produce full density, complex shapes via powder metallurgy. A research target is tool steels where there are opportunities to use SLPS in the near net-shape production of high performance tooling. ***