论文部分内容阅读
针对TiAl合金定向凝固工艺要求,研究了高温长时条件下Ti-47Al-2Cr-2Nb合金熔体对醋酸锆粘接氧化钇模壳的侵渗作用和模壳对合金铸棒的污染状况。结果表明,醋酸锆粘结氧化钇模壳与Ti-47Al-2Cr-2Nb合金在1550,1600,1650℃下保温30min后,TiAl合金熔体的侵渗作用仅限于模壳内表层,模壳整体结构完整,未见合金液渗出。合金铸棒中存在两种夹杂物,一种是Al2O3,一种是由Al2O3和Y-Al-O组成的混合夹杂物。随着保温温度的升高,合金铸棒中夹杂物的尺寸和体积分数明显增加。1650℃保温30min条件下,夹杂物分布在合金铸棒的整个横截面上;1550,1600℃保温30min后,夹杂物从合金铸棒的边缘向中心呈减少趋势;1550℃保温30min条件下,铸棒中的夹杂物基本上仅分布在距边缘约500μm内,至铸棒表面2500μm处已基本没有夹杂物存在。文章对合金铸棒内部夹杂物的形成机理进行了分析。
According to the requirement of directional solidification process of TiAl alloy, the infiltration of Ti-47Al-2Cr-2Nb alloy melt on zirconium acetate bonded yttrium oxide mold shell and the pollution of mold shell on the alloy cast rod were investigated. The results show that the infiltration of TiAl alloy melt is limited to the inner surface of the mold shell and the whole shell of the mold body after the zirconium acetate bonded yttrium oxide mold shell and the Ti-47Al-2Cr-2Nb alloy are incubated at 1550, 1600 and 1650 ° C for 30 minutes Structure is complete, no alloy liquid seepage. There are two kinds of inclusions in alloy casting rod, one is Al2O3, one is mixed inclusions composed of Al2O3 and Y-Al-O. With the increase of holding temperature, the size and volume fraction of inclusions in alloy cast rods increase obviously. The inclusions are distributed on the whole cross-section of the alloy cast rod at 1650 ℃ for 30min. The inclusions decrease from the edge of the alloy cast rod to the center after 1550 and 1600 ℃ for 30min. Under the conditions of 1550 ℃ for 30min, The inclusions in the rod are distributed substantially only within about 500 μm from the edge and substantially no inclusions exist at the surface of the casting rod at 2500 μm. The formation mechanism of inclusions in alloy cast rods is analyzed.