Enhanced sintering treatments for ferrous powders

Abstract

Powder metallurgy (P/M) constitutes a growing metal-forming technology with many favourable attributes. Ferrous materials provide the largest class of P/M alloys. The sintering of iron is examined in this review to establish the fundamental behaviour and to determine possible successes through enhanced sintering treatments. Within the scope of enhanced sintering, both activated and liquid-phase treatments are considered. The available data are collected to determine the effects of various additions on the sintering of iron. It is believed that small additions of elements like phosphorus, boron, carbon, and nitrogen provide for rapid densification and strengthening. However, the benefits are often offset by degradation of other properties such as ductility. These effects, as well as dimensional changes, are documented for several systems. Emphasis is given to describing the atomic processes responsible for the observed changes. There is considerable room for further progress in this area, including fundamental understanding and property optimization.