摘要
以氢化钛、氢化钇、氧化铁和Fe-Cr-W气雾化预合金粉末为原料,通过球磨得到Fe-14Cr-3W-0.5Ti-0.31Y-0.22O合金粉末,经压制、烧结制备出纳米氧化物弥散强化铁素体合金。采用激光粒度仪、XRD、SEM和TEM表征粉末和预烧坯的显微结构。研究结果表明,粉末粒径随球磨时间增加呈先增大后下降,冷焊主导变形机制向破碎主导机制的转变点发生在球磨24h。XRD谱显示氢化物和氧化铁均已溶解于铁素体基体,48h球磨粉末没有发现第二相粒子的存在。球磨48h后过饱和的Y、Ti、O铁素体固溶体在随后的加热过程中析出尺寸为5nm左右的弥散相颗粒,这种第二相粒子非常稳定,即使1200℃保温8h仍不发生明显长大,起着强烈钉扎位错的作用。
By mechanical alloying raw powders of Ti,Y hydrides,iron oxide and gas-atomized Fe-Cr-W powder of the given composition Fe-14Cr-3W-0.5Ti-0.31Y-0.22O,nano-oxide dispersively strengthened ferritic alloys consolidated from pressing and pre-sintering of the as-milled powder were obtained. The morphology of the as-milled powders,the microstructure of the powders and pre-sintered compacts were investigated by means of laser particle sizing,X-ray diffractometry （XRD）,scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. The results show that the average diameter of the milled powder increases first then decreases with the increasing of milling time. The transition point of dominated powder deformation mechanism from cold welding to fracturing is at the milling of 24 h. XRD patterns show that both the hydrides and iron oxide have dissolved completely into ferritic matrix. No second phase particle has been found in the 48 h milled powder. On heat treatment,dispersed particles with an average size of 5 nm were precipitated from the Y,Ti,O supersaturated ferritic solid solution. These second particles which are ultra-stable even at the temperature of 1 200 ℃ holding for 8 h have been found strongly pinning the dislocation lines.
出处
《粉末冶金材料科学与工程》
EI
2010年第1期74-78,共5页
Materials Science and Engineering of Powder Metallurgy
基金
国家自然科学基金资助项目(50634060和50721003)
关键词
机械合金化
氧化物弥散强化
氧化铁
mechanical alloying oxide dispersive strengthen iron oxide
