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针对含0.15%(原子分数)稀土元素Gd的变形γ-TiAl合金,研究1 300℃/0.5h/空冷热处理前后稀土化合物种类、形态和分布变化。变形γ-TiAl合金中存在两种稀土化合物,分别是富Al元素的Al-Gd化合物和富O元素的O-Gd化合物。在热处理过程中Al元素向Al-Gd化合物边缘扩散,基体的Ti、O元素向Al-Gd化合物扩散,因此部分Al-Gd化合物转变为由Al-Gd包围O-Gd的包裹状化合物。热处理后,Al-Gd化合物球化、尺寸减小、数量减少,体积分数由2.78%减少至1.13%,O-Gd化合物数量增加但形貌基本不变。
For the deformed γ-TiAl alloy containing 0.15% (atomic fraction) rare earth element Gd, the change of species, morphology and distribution of rare earth compounds before and after heat treatment at 300 ℃ / 0.5h / air cooling were studied. There are two kinds of rare earth compounds in the deformed γ-TiAl alloy, which are Al-Gd compound rich in Al element and O-Gd compound rich in O element, respectively. During the heat treatment, the Al element diffuses to the edge of the Al-Gd compound, and the Ti and O elements of the matrix diffuse to the Al-Gd compound, so that part of the Al-Gd compound is transformed into the encapsulated compound surrounded by Al-Gd. After heat treatment, the Al-Gd compounds decreased in size and spheroidization, the volume fraction decreased from 2.78% to 1.13%, and the number of O-Gd compounds increased but the morphology remained almost unchanged.