电子束成形TC18钛合金晶体取向规律研究

发布时间：2018-10-21 14:37

【摘要】：采用电子束熔丝成形工艺制备TC18钛合金试件,研究了其柱状晶组织的生长和晶体取向的分布规律。结果表明,用电子束熔丝成形工艺制备的TC18钛合金,其宏观金相组织为沿竖直方向生长的粗大柱状晶,以外延生长的方式从熔池底部长大。受成形过程中特殊传热条件的影响,电子束熔丝成形钛合金组织中的TC18钛合金晶体形成特定方向的择优取向,α、β两相晶体取向分布都有明显的规律。在成形组织外延生长的情况下,β相向α相晶体结构的转变具有继承性。其中大多数β晶粒有001方向的强丝织构,柱状晶间β相的宏观取向也有明显的特征,分布方向集中为TD、LD及法面ND。β→α转变严格遵循Burgers取向关系,由同一个母相β晶粒内析出的片层α/α满足Burgers取向关系所要求的取向差分布,柱状晶内的α主要有6种取向,β→α转变过程有较强的变体选择。
[Abstract]:The growth of columnar crystal structure and the distribution of crystal orientation of TC18 titanium alloy were studied by electron beam fuse forming process. The results show that the macrostructure of TC18 titanium alloy prepared by electron beam fusing process is a coarse columnar crystal grown in vertical direction and grown from the bottom of the molten pool by epitaxial growth. Under the influence of the special heat transfer conditions during the forming process, the TC18 titanium alloy crystals formed by the electron beam fusing wire formed the preferred orientation in a particular direction, and the orientation distribution of 伪 and 尾 two-phase crystals had obvious regularity. The transformation of 尾 -phase to 伪 phase crystal structure is inherited under the condition of epitaxial growth of formed microstructure. Most of the 尾 grains have strong filamentous texture in 001 direction, and the macroscopic orientation of columnar intergranular 尾 phase is also obvious. The distribution direction is TD,LD and ND. 尾伪 transition of normal plane strictly follow the Burgers orientation relation. The lamellar 伪 / 伪 precipitated in the same parent phase satisfies the orientation difference distribution required by the Burgers orientation relationship. The 伪 in the columnar crystal has six main orientations, and the 尾伪 transition process has a strong variant selection.
【作者单位】：北京航空制造工程研究所高能束流加工技术重点实验室;北京科技大学材料科学与工程学院;
【基金】：国家自然科学基金(51205178) 甘肃省自然科学基金(1208RJZA189)~~
【分类号】：TG146.23;TG661

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