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通过直接热处理方法细化铸态及热等静压态的Ti-47Al-2Cr-2Nb合金组织,选用10mm×10mm×12mm及15mm×30mm两种尺寸试样进行热处理实验,探讨原始铸态组织对热处理组织细化效果,以及试样尺寸对热处理组织均匀性的影响。结果表明:对10mm×10mm×12mm小尺寸试样,铸态和热等静压态试样淬火组织分别是块状转变组织和斑驳状组织,经过循环热处理后,两种组织均可获得50μm以下的均匀等轴状全片层组织;铸锭的致密部位组织经循环热处理后,无淬火裂纹出现,含缺陷较多的试样经热处理后淬裂现象严重。对15mm×30mm大尺寸试样,铸态试样经过淬火后中心出现热处理裂纹,试样内部组织转变不均匀。
The as-cast and hot isostatically pressed Ti-47Al-2Cr-2Nb alloy structures were refined by direct heat treatment. Heat treatment experiments were carried out on the samples of 10mm × 10mm × 12mm and 15mm × 30mm, Effect of heat treatment on the microstructure refinement and sample size on the uniformity of heat treatment. The results show that the as-quenched microstructure of as-cast and hot-isostatically pressed samples are bulk-transformed and mottled, respectively. For the small size of 10mm × 10mm × 12mm, Of the uniform equiaxed the entire slice organization; ingot dense parts of the organization after heat treatment cycle, no quenching cracks appear, with more defects in the sample after heat treatment quench cracking phenomenon is serious. For 15mm × 30mm large-size specimens, the as-cast specimens were heat-treated at the center of the quenched specimen and the microstructure of the as-cast specimens was not uniformly transformed.