铁基粉末冶金高密度压坯成形与烧结行为及其控制

粉末冶金工艺在制造机械零件时能够少切削或无切削，具有材料利用率高、能耗低等特点，已发展成为一种重要的复杂形状零部件近终形制造技术。残留孔隙是影响粉末冶金材料性能和其产品在关键领域扩大应用的瓶颈。本项目以粉末冶金工业中产量最大、应用最广的铁基粉末冶金为研究对象，针对传统压制-烧结产品密度低、零件烧结变形等问题，基于聚合物共混原理，提出了通过设计新型润滑剂，综合利用其减摩、粘结和触变等多功能特性，提高压坯密度及其均匀性的新思路。通过重点研究多组元多功能润滑剂设计与调控原理、混合粉末的润滑行为与压制致密化规律、高密度压坯在烧结过程中的原子迁移行为与相变规律等科学问题，为发展高密度、高性能、高精度铁基粉末冶金结构零件的低成本制造技术奠定理论和技术基础。该研究对发展高性能铁基粉末冶金材料、扩大铁基粉末冶金产品的应用领域有积极的推动作用，具有重要的理论意义和经济价值。

Powder metallurgy has emerged as an net or near-net shape processing for fabricating mechanical components, exhibiting characteristics of high utilization of materials and low energy consuming. The residual pores in sintered compact are the bottleneck problem for the mechanical properties and the application of powder metallurgy products in critical industrial sectors. The project will take the ferrous powder metallurgy as research objects, which is the most important field in powder metallurgy industry concerning with its output and application. In view of the problems of low compact density and sintering distortion of traditional compact-sintering processing, the comprehensive utilization of the mechanisms of antifriction, bonding and thixotropism of lubricants, through designing new multi-functional lubricants based on the theory of polymer blends, was proposed to increase the compact density and its homogeneity. The main focuses are on the model of multi-functional lubricants, the consolidation behaviors of lubricated powder mixture, as well as the migration behavior of the atoms during sintering and the mechanisms of phase transformation. This project is expected to exert positive effect on the establishment of theoretical and technological foundation for the low-cost fabrication of ferrous powder metallurgy components with high density, high performance and high precision, which is of crucial theoretical and economic importance.