Innovative processing of high-strength and low-cost ferritic steels strengthened by Y-Ti-O nanoclusters

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• 作者：Yuren Wen^a ; ^b ; Yong Liu^a ; ^{yonliu11@yahoo.com.cn} ; Akihiko Hirata^b ; ^c ; Feng Liu^a ; Takeshi Fujita^b ; ^c ; Yuhai Dou^a ; Donghua Liu^a ; Bin Liu^a ; Zuming Liu^a ; C.T. Liu^d
• 关键词：ODS ferritic steel ; Mechanical alloying ; Transmission electron microscopy (TEM) ; Precipitation
• 刊名：Materials Science and Engineering ; A
• 出版年：2012
• 期刊代码：61_09215093
• 类别：ms
• 出版时间：15 May, 2012
• 卷：544
• 期：Complete
• 页码：59-69
• 文件大小：3992 K

摘要

Nanostructured ferritic alloys (NFAs) have been essentially fabricated by mechanical alloying pre-alloyed ferritic powders with Y₂O₃. In this work, Y₂O₃ was replaced by Y hydride and more soluble Fe₂O₃ to prepare NFAs. The microstructural characterization concerning the formation of nanoparticles and mechanical property of NFAs prepared by the novel process were investigated. It is found, during mechanical alloying both Fe₂O₃ and hydride can be easily dissolved into the ferritic matrix. Coherent Y-Ti-O nanoparticles with a pyrochlore Y₂Ti₂O₇ structure and incoherent Cr-rich oxides were precipitated after the hot consolidation. With an increased milling time, there exists a shift of oxygen from the Cr-rich oxides to Y-Ti-O nanoparticles, resulting in a significantly homogeneous dispersion of nanoparticles. Compared with 14YWT, the NFAs in this work show a combination of high strength and improved ductility. Thus, the addition of Fe₂O₃ as an oxygen carrier provides an alternate way to adjust the oxygen content, which does not require high energy milling; and the combination of hot forging and hot rolling processes, rather than the hot extrusion are more cost-effective.