(重庆大学 材料科学与工程学院,重庆 400044)
摘 要: 为研究TA17近α钛合金在高能喷丸(HESP)过程中的晶粒细化机制,采用高能喷丸对TA17近α钛合金棒材端面进行处理,利用光学显微镜(OM)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和X射线衍射仪对喷丸变形层组织进行表征,按照变形层中不同深度的组织特征对晶粒细化机制进行探讨。结果表明:在喷丸表面形成35 nm左右的等轴纳米晶,在孪晶形成层中粗晶内形成较厚的孪晶薄片,在过渡层中位错滑移使孪晶薄片内生成小角度取向的亚晶,在纳米层中亚晶被转变成随机取向的等轴纳米晶。
关键字: 钛合金;高能喷丸;纳米晶;孪生;位错
(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