摘要
采用氩气气氛下真空感应熔炼的方式制备了TiAl_(45)Nb_(10)-xBe(x=0,0.5%,1.0%,1.5%,2.0%,原子数分数,下同)合金,使用金相显微镜(OM)、扫描电镜(SEM)、能谱仪(EDS)、X射线衍射(XRD)、万能试验机等对合金显微组织、力学性能和高温氧化行为进行研究,讨论了高温下合金的抗氧化机理.结果表明:合金主要由γ-TiAl相和α_(2)-Ti_(3)Al相构成;Be能够细化合金的显微组织,促进其从片层结构向双态结构转变;在1273 K下氧化75 h后,合金显微组织从片层结构完全转变为双态结构并一直保持,较小的双态等轴晶使合金的塑性在牺牲部分强度和硬度后得到提高.合金在1273 K下的氧化动力学符合抛物线规律,氧化速率随Be含量的增加缓慢减小,并在50 h后进入稳定氧化阶段.由TiO_(2)+BeO/Al_(2)O_(3)+BeO/Nb2O5+BeO构成的狭长带状氧化层以交替生长的方式向合金基体内部生长,表现出一定的抗氧化性.综合来看,1.5%Be合金在显微组织和抗氧化性能方面表现突出.
TiAl_(45)Nb_(10)-xBe(x=0,0.5%,1.0%,1.5%,2.0%,atomic number fraction,the same below)alloys were prepared by vacuum induction melting under argon atmosphere,and the microstructure,mechanical properties,and high-temperature oxidation behaviors of the alloys were investigated by using optical microscope(OM),scanning electron microscope(SEM),energy dispersive spectroscopy(EDS),X-ray diffraction(XRD)and universal testing machine.The results show that the alloys are mainly composed ofγ-TiAl phase andα_(2)-Ti_(3)Al phase.Be can refine the microstructures of the alloys,and promote the microstructures of the alloys from lamellar structure to double phase structure.After oxidation at 1273 K for 75 h,the alloy microstructure completely transforms from lamellar structure to double phase structure and remains so.The smaller bimodal equiaxed crystals improve the plasticity of the alloy at the expense of some strength and hardness.The oxidation kinetics of the alloy at 1273 K follow the parabolic law,and the oxidation rate decreases slowly with the increase of Be content and enters the stable oxidation stage after 50 h.The narrow strip-shaped oxide layer composed of TiO_(2)+BeO/Al_(2)O_(3)+BeO/Nb2O5+BeO grows towards the inner part of the alloy matrix in an alternating manner,which shows a certain degree of oxidation resistance.In general,the 1.5%Be alloy shows outstanding performance in terms of microstructure and oxidation resistance.
作者
王威
霍雨晗
Wang Wei;Huo Yuhan(School of Material Science and Engineering,Heilongjiang Institute of Technology,Harbin 150050,China)
出处
《材料与冶金学报》
北大核心
2025年第3期279-285,共7页
Journal of Materials and Metallurgy
基金
黑龙江省大学生创新创业训练计划项目(S202311802027).
作者简介
王威(1978-),男,讲师,E-mail:wwacme@126.com.
