(重慶大學(xué) 材料科學(xué)與工程學(xué)院，重慶 400044)
摘 要: 為研究TA17近α鈦合金在高能噴丸(HESP)過程中的晶粒細(xì)化機(jī)制，采用高能噴丸對TA17近α鈦合金棒材端面進(jìn)行處理，利用光學(xué)顯微鏡(OM)、掃描電子顯微鏡(SEM)、透射電子顯微鏡(TEM)和X射線衍射儀對噴丸變形層組織進(jìn)行表征，按照變形層中不同深度的組織特征對晶粒細(xì)化機(jī)制進(jìn)行探討。結(jié)果表明：在噴丸表面形成35 nm左右的等軸納米晶，在孿晶形成層中粗晶內(nèi)形成較厚的孿晶薄片，在過渡層中位錯滑移使孿晶薄片內(nèi)生成小角度取向的亞晶，在納米層中亞晶被轉(zhuǎn)變成隨機(jī)取向的等軸納米晶。
關(guān)鍵字: 鈦合金；高能噴丸；納米晶；孿生；位錯
（College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China）
Abstract:In order to research the mechanism of grain refinement in TA17 near α Ti alloy, the cross section surface of TA17 near α Ti alloy bars were treated by high energy shot peening(HESP). The microstructures feature in plastic deformation layer were characterized and researched by optical microscopy(OM), scanning electron microscopy(SEM), transmission electron microscopy(TEM) and X-ray diffraction(XRD). The grain refinement mechanism was researched according to different depth microstructures feature in the deformation layer. The results show that the equiaxed nanograins with about 35 nm are synthesized on the peening surface. In the twin forming layer, the twin lamellas are generated in coarse grains. In the transition layer, twin lamellars are transformed into with small angle by dislocation slip. And in the nanometer crystalline grain layer, subgrain are transformed into randomly oriented equiaxed nanograins.
Key words: titanium alloy; high energy shot peening; nanograin; twin; dislocation slip
