低压粉末注射成型FeCrAl合金成型性能的研究

采用低压粉末注射成型技术制备FeCrAl多孔材料，并研究了粘结剂配比和温度对其成型特性的影响。将FeCrAl合金粉末与不同配方的粘结剂混合，分别采用差示扫描量热仪（differential scanning calorimetry, DSC）、热重分析仪（thermogravimetric analyzer, TGA）和旋转流变仪测试混合物的熔化温度、分解温度以及不同转速和温度下的黏度，计算原料体系的塑性成型指数。结果表明，不同粘结剂配比和不同温度下，原料的流变行为和成型特性不同。成型温度越高，黏度越低，成型性越好。相同温度下，石蜡和石蜡/硬脂酸配方成型性较好，但原料在高转速下易分层，且压注样品在溶液脱脂过程中发生溃散；采用石蜡/低密度聚乙烯/硬脂酸和石蜡/乙酸乙烯共聚物/硬脂酸配方制备的样品，成型性较好，且高转速下原料稳定。采用石蜡/低密度聚乙烯/硬脂酸配方制备的样品，经脱脂烧结后，外观完好，粉末之间呈现冶金结合，维氏硬度为210，抗弯强度为（250±20）MPa。

Study on the Formability of FeCrAl Alloy by Low Pressure Powder Injection Molding

FeCrAl porous materials were prepared by using low pressure powder injection molding technology, and the effects of binder ratio and temperature on its forming characteristics were studied. FeCrAl alloy powder was mixed with different formulations of binders, and differential scanning calorimetry (DSC), thermogravimetry analyzer (TGA) and rotary rheometer were used to measure the melting temperature, decomposition temperature and viscosity of the mixture at different speeds and temperatures, respectively. The plastic forming index of the raw material system was calculated. The results indicate that the rheological behaviors and molding characteristics of raw materials are different under different binder ratios and different temperatures. The higher the molding temperature is, the lower the viscosity is, and the better the moldability is. At the same temperature, the formability of paraffin and paraffin/stearic acid are better. However, the raw material is easy to delaminate at high speed, and the pressure injection sample is collapsed in the process of solution degreasing. The samples prepared by paraffin/low density polyethylene/stearic acid and paraffin/vinyl acetate copolymer/stearic acid have good formability and stable raw materials at high speed. The samples prepared by paraffin/low density polyethylene/stearic acid, after degreasing and sintering, have good appearance and show metallurgical bonding between powders with Vickers hardness of 210 and bending strength of (250±20) MPa.