Microwave processing, characterizationand modeling of metal powder compacts

本项目的主要目标是对用于生产改进机械部件的金属粉末的烧结行为进行系统的研究和详细的实验研究。通过将整个领域分为建模、表征和处理三个部分，可以实现对微波烧结现象不同方面的系统研究。首先，用不同生坯密度的常用金属粉末压坯制成一批样品，用单轴压制的方法制备。建模将涉及将这些粉末压坯实现为专门的复合材料，并根据体积比和每个组分的材料属性来计算这些样品的有效介电和磁性。为了进行表征，将测量每个样品的散射系数，以确定这些样品的有效电磁特性，然后将其与其理论值进行比较。在工艺方面，大部分样品的烧结将在基于回旋管的高功率微波系统中进行。通过改变样品的成分和生坯密度，对样品在烧结过程中的温度分布和直流电导率进行在线测量，并与常规方法进行比较。这些研究将借助扫描电子显微镜、能谱和光学显微镜进行详细的分析，以全面了解观察到的效果。

The main goal of this project is to carry out a systematic study and the detailed experimental investigations on sintering behaviors of metal powders commonly used for the production of improve machine components. The systematic approach to study different aspects of the microwave sintering phenomenon would be achieved by dividing the overall field into three parts, namely, the modeling, the characterization and the processing. First of all, a number of samples made of commonly used metal powder compacts with different green densities will be prepared by uni-axial pressing. The modeling would involve the realization of these powder compacts as specialized composites, and computing the effective dielectric and magnetic properties of these samples in terms of the volume ratio and the material properties of each constituent. For the characterization, the scattering coefficients of each sample will be measured in order to determine the effective electromagnetic properties of these samples, which would then be compared with their theoretical values. On the processing front, the sintering of most of the samples would be performed in a gyrotron based high power microwave system. It is planned to carry out online measurements of temperature distribution and the DC conductivity during the sintering process of these samples by varying their composition and the green density, and comparing the results with the conventional methods. These investigations will be analyzed in detail with the help of SEM, EDX and the optical microscopy in order to fully understand the observed effects.