先进氧化物弥散强化钢制备技术研究进展

Research progress for manufacturing technology of advanced oxide dispersion strengthened steel

采用先进氧化物弥散强化(ODS)技术制备出的氧化物弥散强化钢具有优异的力学性能和耐蚀性能。对ODS钢铁材料的配粉技术、制备工艺、微观结构、力学性能和强化机制进行了阐述。ODS钢原料中高品质第二相粒子和金属粉体是制备基础,将纳米结构氧化物粒子添加到金属基体中,常采用球磨合金化法制备出金属粉末原料,其中Y2O3、Al2O3等纳米氧化物是ODS钢常用的弥散强化粒子。ODS钢铁材料的组织和性能取决于其制备工艺,传统冶炼铸造法制备ODS钢较困难,而粉末冶金法制备ODS钢较为常用,包括热挤压法、热等静压法、放电等离子烧结法等;增材制造工艺是制备ODS钢的新途径,特别是选区激光熔化法已经用于研制ODS不锈钢。Y2O3粒子ODS钢中,易与氧结合的金属元素(Ti、Al、Zr等)与固溶到基体中的Y和O元素发生反应后,以复杂氧化物形式析出并赋存于微观组织中。大量弥散分布的第二相粒子钉扎晶界和位错,阻碍位错运动,从而起到弥散强化效果,提高了先进ODS钢的力学性能和耐蚀性能,扩大了其应用范围。

Advanced oxide dispersion strengthened(ODS) technology prepared oxide dispersion strengthened steel has excellent mechanical properties and corrosion resistance. The powder mixing technology, preparation process, microstructure, mechanical properties and strengthening mechanism of ODS steel are described. High quality second phase particles and metal powder are the basis of ODS steel raw materials preparation. Nano-structured oxide particles are added to the metal matrix, and metal powder raw materials are usually prepared by ball milling alloying method. Among them, Y2O3, Al2O3and other nano-oxides are commonly used as dispersion strengthened particles of ODS steel. Microstructure and mechanical properties of ODS steel material depends on its preparation technology, the traditional smelting and casting method for ODS steel preparation is relatively difficult, while powder metallurgy method is commonly used, including hot extrusion, hot isostatic pressure, the spark plasma sintering process and so on. Additive manufacturing technology is a new way for preparation of ODS steel, especially selective laser melting method has been used to develop the ODS stainless steel. In Y2O3-containing ODS steel, the metal elements(Ti, Al, Zr, etc.) that are easy to combine with oxygen react with Y and O in the matrix, and then precipitate in the form of complex oxides in the microstructure. A large number of dispersive distributed second phase particles can nail grain boundaries and dislocation and hinder dislocation movement, thus playing a dispersion strengthening effect, improving the mechanical properties and corrosion resistance of advanced ODS steel and expanding its application range.