Component Shape Retention in Liquid Phase Sintering of Prealloyed Powders

邮编：9610280 超固相线液相烧结（SLPS）的新研究解决了三个问题。 第一个检查在加热和烧结过程中的微观结构演变。 目前的工艺模型假设了晶粒生长速率、液膜厚度、收缩率、半固体颗粒粘度和变形原因。 这些假设是解决模型系统使用淬火样品和原位测试的微观结构测量进行实验。 目标是增加模型的真实性，并识别系统之间的任何行为。 第二个主题是最终部件尺寸和形状的预测。 液体在晶界上扩散时结构刚度损失的计算预测需要验证。 此外，晶粒尺寸、颗粒尺寸、堆积密度、基底摩擦和热传递的梯度需要包括在最终部件尺寸和形状预测中。 第三项活动将模型扩展到其他几种加工条件（双峰尺寸粉末，不同成分的粉末，高粘度系统，反应系统）。 这项研究的成功将对SLPS工艺的使用产生积极影响，通过粉末冶金生产全密度复杂形状。 研究目标是工具钢，在那里有机会使用SLPS在近净形生产的高性能工具。 ***

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. ***