(1. 上海工程技術(shù)大學(xué) 材料工程學(xué)院，上海 201620；
2. 上海交通大學(xué) 材料科學(xué)與工程學(xué)院，上海 200240)
摘 要: 采用表面機(jī)械研磨技術(shù)在定向凝固態(tài)和鑄造態(tài)Ni3Al表面制備納米結(jié)構(gòu)表層，采用掃描電鏡、XRD和TEM等對納米結(jié)構(gòu)表層的組織特征進(jìn)行研究，探討定向凝固和鑄造兩種制備狀態(tài)對Ni3Al表面納米結(jié)構(gòu)組織特征的影響。結(jié)果表明：經(jīng)過相同工藝表面機(jī)械研磨處理后，兩種制備狀態(tài)的Ni3Al發(fā)生了無序化轉(zhuǎn)變和晶粒細(xì)化，但兩者的表層組織特征間存在顯著差異；鑄造態(tài)Ni3Al試樣中Ni(Al)固溶體的含量達(dá)65%，遠(yuǎn)高于定向凝固態(tài)Ni3Al試樣中的7%；鑄造態(tài)試樣表層的晶粒尺寸約為56 nm，遠(yuǎn)大于定向凝固態(tài)試樣的22 nm；兩種Ni3Al試樣制備態(tài)時(shí)，化學(xué)成分和顯微硬度的差異可能是造成這種差異的原因。
關(guān)鍵字: 金屬間化合物；Ni3Al；表面機(jī)械研磨處理；塑性變形；微觀組織
surface nanocrystallized Ni3Al
（1. College of Materials Engineering, Shanghai University of Engineering Science, Shanghai 201620, China;
2. School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China）
Abstract:The influence of two initial states, such as directional solidified and as-cast, on the microstructure of surface of nanocrystallized Ni3Al was investigated. The nanostructure layers were prepared on the surface of Ni3Al with different initial states by means of surface mechanical attrition treatment (SMAT). The characteristics of surface nanostructure layer were examined by scanning electronic microscopy (SEM), X-ray diffractometry (XRD) and transmission electronic microscopy (TEM). The results indicate that the transformations, such as disordering and grain refining, occur in all samples with different initial states after surface mechanical attrition treatment. However, obvious difference exists in the relative content of solid solution and the grain size of Ni3Al nanograins between the samples with two initial states. The Ni(Al) solid solution of as-cast Ni3Al surface reaches 65% and the grain size is about 56nm after surface mechanical attrition treatment. The directional solidified Ni3Al has less Ni(Al) solid solution (7%) and smaller grains (abut 22nm). This phenomenon may be attributed to the difference of the two initial states in chemical composition and microhardness.
Key words: intermetallic; Ni3Al; surface mechanical attrition treatment; plastic deformation; microstructure
