硼及钇对钛铝合金组织性能的影响及精密铸造工艺研究
发布时间：2019-02-22 11:08
【摘要】：熔模铸造是制备具有工程应用背景的TiAl合金构件的重要生产方式,本文研究了硼、钇对铸态TiAl合金的组织性能的影响,以及热处理对TiAl合金的组织性能的影响,开展了适合TiAl合金熔模铸造用陶瓷型壳面层材料的研究,探索了大型TiAl合金铸件的浇注工艺,进行了大型TiAl合金格栅件的浇注。研究发现Y有强烈的吸氧作用,Ti-45Al-5Nb-0.08Y合金的氧含量从Ti-45Al-5Nb合金的740ppm降至460ppm。微量Y的添加能够细化Ti-45Al-5Nb合金α2/γ片层的片层间距,Ti-45Al-5Nb-0.08Y合金的片层间距从Ti-45Al-5Nb合金的580nm降至200nm。但微量Y的添加对Ti-45Al-5Nb合金晶粒尺寸的影响不明显,含Y合金的晶粒尺寸仍约为770μm。Ti-45Al-5Nb-x Y合金中的富钇相为Y2O3相,YAl O3相和Al Y相,其中有共格关系1213]YAl O3//[101]Y2O3。添加Y可改善铸态Ti-45Al-5Nb合金的室温力学性能。研究发现B的添加可以显著细化合金组织,0.4%B为Ti-45Al-5Nb合金铸态组织最佳细化效果的最小B添加量。Ti-45Al-5Nb-x B合金中的硼化物为遵守[001]Bf//[001]D7b//[001]B2共格关系的三相复合条带。B对Ti-45Al-5Nb铸态合金的细化机制为凝固前沿的成分过冷。铸态Ti-45Al-5Nb-0.4B合金室温力学性能最好。研究发现Ti-45Al-5Nb-0.4B-x Y(x=0.02,0.04,0.06,0.08,at.%)合金中由于B和Y的复合作用,合金中硼化物为Bf相条带与YBO3相薄片垂直生长,两相之间存在如下的共格关系:[001]Bf//[010]YBO3。在YBO3相生长过程中消耗了氧化钇,残余的富钇相为Al Y和Al2Y。铸态Ti-45Al-5Nb-0.4B-0.06Y合金的室温力学性能最好。研究发现含硼、钇的TiAl合金经过全片层热处理,Ti-45Al-5Nb-0.4B-0.06Y合金的室温拉伸强度为709MPa,伸长率为0.63%。含硼、钇的TiAl合金经过双态热处理,Ti-45Al-5Nb-0.4B-0.06Y合金的室温拉伸强度为706MPa,伸长率为0.67%。研究了锆粘结剂、钨粘结剂、钇粘结剂、铝粘结剂四种粘结剂的晶化行为,确定碳酸锆铵粘结剂、偏钨酸铵粘结剂、钇溶胶粘结剂制备的型壳的焙烧温度为950°C,铝溶胶粘结剂制备的型壳的焙烧温度为1100°C。分析了反应界面的形貌、元素分布和显微硬度,综合考虑界面平直程度、粘砂层致密程度、是否有TiAl合金侵入型壳、TiAl合金基体中是否有耐火材料颗粒夹杂、反应层厚度、粘砂层厚度、铸件表面硬度和硬化层厚度等因素,发现Al-Sol+Al2O3面层型壳与TiAl合金的界面反应最轻微,反应层厚度仅为2μm,且无粘砂层。基于小尺寸TiAl合金格栅试验件的Pro CAST数值模拟确定工艺方案,利用模拟所得最佳参数进行实际浇注实验,成功制备出TiAl合金格栅试验件。对TiAl合金格栅试验件分析表明,铸件组织均匀,从Qg圆到外边缘无明显变化。缩松缩孔缺陷分散分布于圆盘,模拟结果与实验结果吻合。基于小尺寸试验件的数值模拟和实际浇注的数据,优化了TiAl合金格栅件的浇注系统,成功制备出高质量的大型(Φ580×10mm)TiAl合金格栅件。
[Abstract]:Investment casting is an important method of producing TiAl alloy components with engineering application background. The effects of boron and yttrium on the microstructure and properties of as-cast TiAl alloys and the effects of heat treatment on the microstructure and properties of TiAl alloys are studied in this paper. The study of ceramic shell layer material suitable for TiAl alloy investment casting was carried out, the pouring process of large TiAl alloy casting was explored, and the pouring of large TiAl alloy grille was carried out. It was found that Y had strong oxygen absorption, and the oxygen content of Ti-45Al-5Nb-0.08Y alloy decreased from 740ppm of Ti-45Al-5Nb alloy to 460 ppm. The addition of trace Y can refine the lamellar spacing of Ti-45Al-5Nb alloy 伪 _ 2 / 纬, and the interlamellar spacing of Ti-45Al-5Nb-0.08Y alloy decreases from 580nm of Ti-45Al-5Nb alloy to 200 nm. However, the effect of trace Y addition on the grain size of Ti-45Al-5Nb alloy is not obvious. The grain size of Y containing alloy is still about Y2O3 phase, YAl O3 phase and Al Y phase in 770 渭 m.Ti-45Al-5Nb-x Y alloy. There is a coherent relation 1213] YAl O _ 3 / [101] Y _ 2O _ 3. The mechanical properties of as-cast Ti-45Al-5Nb alloy at room temperature can be improved by adding Y. It was found that the addition of B could significantly refine the microstructure of the alloy. 0.4B is the minimum B addition for the best refining effect of Ti-45Al-5Nb alloy. The borides in Ti-45Al-5Nb-x B alloy are conformable to [001] Bf// [001] D7b// [001] B2. The refining mechanism of Ti-45Al-5Nb alloy is supercooled at the front of solidification. As-cast Ti-45Al-5Nb-0.4B alloy has the best mechanical properties at room temperature. It was found that the boride in Ti-45Al-5Nb-0.4B-x Y (x 0. 02 0. 04) alloy was grown perpendicular to the Bf phase strip and the YBO3 phase sheet due to the complex action of B and Y. There is the following coherent relation between the two phases: [001] Bf// [010] YBO3. Yttrium oxide was consumed during the growth of YBO3 phase, and the residual rich phase was Al Y and Al2Y.. As-cast Ti-45Al-5Nb-0.4B-0.06Y alloy has the best mechanical properties at room temperature. It was found that the tensile strength and elongation of TiAl alloy containing boron and yttrium were 709 MPA and 0.63 respectively. The tensile strength of TiAl alloy containing boron and yttrium is 706 MPA at room temperature and the elongation is 0.67 MPA after double state heat treatment. The crystallization behavior of zirconium binder, tungsten bond agent, yttrium bond agent and aluminum bond agent was studied. The calcination temperature of the shell prepared by ammonium zirconium carbonate binder, ammonium metatungstate binder and yttrium sol adhesive was 950 掳C. The calcination temperature of the shell prepared by aluminum sol binder is 1100 掳C. The morphology, element distribution and microhardness of the reaction interface were analyzed. Considering the level of interface flatness, the density of sand layer, whether there were TiAl alloy intrusive shell, whether there were refractory particles in TiAl alloy matrix, the thickness of reaction layer was considered. It is found that the interface reaction between Al-Sol Al2O3 shell and TiAl alloy is the least, the thickness of reaction layer is only 2 渭 m, and there is no sand layer. Based on the Pro CAST numerical simulation of the small size TiAl alloy grille test piece, a practical casting experiment was carried out by using the optimum parameters obtained from the simulation, and the TiAl alloy grille test piece was successfully prepared. The analysis of TiAl alloy grille shows that the casting structure is uniform and there is no obvious change from the Qg circle to the outer edge. The defect of shrinkage is dispersed on the disk, and the simulation results are in agreement with the experimental results. Based on the numerical simulation of small size test pieces and the actual pouring data, the gating system of TiAl alloy grille was optimized, and a large (桅 580 脳 10mm) TiAl alloy grid with high quality was successfully prepared.
【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TG146.2;TG249.5
本文编号：2428157
[Abstract]:Investment casting is an important method of producing TiAl alloy components with engineering application background. The effects of boron and yttrium on the microstructure and properties of as-cast TiAl alloys and the effects of heat treatment on the microstructure and properties of TiAl alloys are studied in this paper. The study of ceramic shell layer material suitable for TiAl alloy investment casting was carried out, the pouring process of large TiAl alloy casting was explored, and the pouring of large TiAl alloy grille was carried out. It was found that Y had strong oxygen absorption, and the oxygen content of Ti-45Al-5Nb-0.08Y alloy decreased from 740ppm of Ti-45Al-5Nb alloy to 460 ppm. The addition of trace Y can refine the lamellar spacing of Ti-45Al-5Nb alloy 伪 _ 2 / 纬, and the interlamellar spacing of Ti-45Al-5Nb-0.08Y alloy decreases from 580nm of Ti-45Al-5Nb alloy to 200 nm. However, the effect of trace Y addition on the grain size of Ti-45Al-5Nb alloy is not obvious. The grain size of Y containing alloy is still about Y2O3 phase, YAl O3 phase and Al Y phase in 770 渭 m.Ti-45Al-5Nb-x Y alloy. There is a coherent relation 1213] YAl O _ 3 / [101] Y _ 2O _ 3. The mechanical properties of as-cast Ti-45Al-5Nb alloy at room temperature can be improved by adding Y. It was found that the addition of B could significantly refine the microstructure of the alloy. 0.4B is the minimum B addition for the best refining effect of Ti-45Al-5Nb alloy. The borides in Ti-45Al-5Nb-x B alloy are conformable to [001] Bf// [001] D7b// [001] B2. The refining mechanism of Ti-45Al-5Nb alloy is supercooled at the front of solidification. As-cast Ti-45Al-5Nb-0.4B alloy has the best mechanical properties at room temperature. It was found that the boride in Ti-45Al-5Nb-0.4B-x Y (x 0. 02 0. 04) alloy was grown perpendicular to the Bf phase strip and the YBO3 phase sheet due to the complex action of B and Y. There is the following coherent relation between the two phases: [001] Bf// [010] YBO3. Yttrium oxide was consumed during the growth of YBO3 phase, and the residual rich phase was Al Y and Al2Y.. As-cast Ti-45Al-5Nb-0.4B-0.06Y alloy has the best mechanical properties at room temperature. It was found that the tensile strength and elongation of TiAl alloy containing boron and yttrium were 709 MPA and 0.63 respectively. The tensile strength of TiAl alloy containing boron and yttrium is 706 MPA at room temperature and the elongation is 0.67 MPA after double state heat treatment. The crystallization behavior of zirconium binder, tungsten bond agent, yttrium bond agent and aluminum bond agent was studied. The calcination temperature of the shell prepared by ammonium zirconium carbonate binder, ammonium metatungstate binder and yttrium sol adhesive was 950 掳C. The calcination temperature of the shell prepared by aluminum sol binder is 1100 掳C. The morphology, element distribution and microhardness of the reaction interface were analyzed. Considering the level of interface flatness, the density of sand layer, whether there were TiAl alloy intrusive shell, whether there were refractory particles in TiAl alloy matrix, the thickness of reaction layer was considered. It is found that the interface reaction between Al-Sol Al2O3 shell and TiAl alloy is the least, the thickness of reaction layer is only 2 渭 m, and there is no sand layer. Based on the Pro CAST numerical simulation of the small size TiAl alloy grille test piece, a practical casting experiment was carried out by using the optimum parameters obtained from the simulation, and the TiAl alloy grille test piece was successfully prepared. The analysis of TiAl alloy grille shows that the casting structure is uniform and there is no obvious change from the Qg circle to the outer edge. The defect of shrinkage is dispersed on the disk, and the simulation results are in agreement with the experimental results. Based on the numerical simulation of small size test pieces and the actual pouring data, the gating system of TiAl alloy grille was optimized, and a large (桅 580 脳 10mm) TiAl alloy grid with high quality was successfully prepared.
【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TG146.2;TG249.5
【参考文献】
相关期刊论文 前1条
1 王艳晶;李菲;谷艳鹏;王继杰;杜兴蒿;;Ti-45Al-8(Nb,Hf,Y)-0.2B合金的高温抗氧化性[J];稀有金属材料与工程;2016年01期
，本文编号：2428157
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