【摘要】 在无籽晶的生长条件下,利用光学浮区定向凝固炉制备了Ti-44.5Al-3Nb-0.8Si-0.2C合金定向试棒。从试棒中切取择优取向的晶粒作为籽晶,引晶自身并成功得到片层界面平行生长方向的定向试棒。结果表明,该试棒的室温屈服强度约为722 MPa,伸长率约为3.9%。SEM观察发现,大量条形硅化物在片层组织中析出。实验结果表明:该合金片层组织具有较好的热稳定性,具备引晶功能,但硅化物的存在使得合金室温塑性略低。更多还原

【Abstract】 Directionally solidified Ti-44. 5Al-3Nb-0. 8Si-0. 2C alloy bar was prepared without seed in an optical floating zone furnace. The preferred grain of the ingot served as the seed in the seeding process and directionally solidified bar with lamellar boundaries parallel to the growth direction was obtained. The results show that room temperature tensile yield strength of the alloy is 722 MPa,tensile elongation is3. 9%. Plenty of silicide particles are observed in the alloy by SEM,and lamellar structure of the alloy is thermally stable enough to act as the seed material,silicide particles may be the reason for relatively low tensile elongation.更多还原