摘要
采用两步法热扩散技术在K417G合金上制备了NiCrAlY涂层,涂层试样的拉伸试验分别在室温与900℃进行,旋转弯曲疲劳试验在室温下进行。研究了涂层对合金拉伸强度、疲劳寿命的影响及疲劳断裂机理。结果表明:室温和900℃条件下,施加涂层提高了合金的屈服强度,降低了合金的抗拉强度;室温下的涂层试样的疲劳极限强度比合金降低了50MPa,相同应力条件下涂层降低了合金的疲劳寿命;涂层NiAl相的本征脆性和涂层内部缺陷降低了基体合金的拉伸性能,并引发了疲劳裂纹的萌生与扩展。
Co-deposited NiCrAlY coatings were prepared on a Ni-based superalloy K417G by a two-step diffusion method.Tensile tests of the samples were carried out at room temperature and 900 ℃,respectively.The rotary bending fatigue tests were carried out at room temperature.The tensile strength,fatigue strength,fatigue fracture mechanism of the coated samples and the bulk materials were compared.The results show that the tensile strength of the coated samples is reduced;however,yield strength is improved at both room temperature and 900 ℃.The fatigue limit strength of the coated samples decreases by 50 MPa compared with the bare alloy.Under the same stress conditions,the fatigue life of the coated samples is lower than the alloy matrix.The intrinsic brittleness of NiAl phase and internal defects in the coating result in poor tensile properties of the coated samples,leading to initiation and propagation of fatigue crack.
出处
《中国表面工程》
EI
CAS
CSCD
北大核心
2013年第3期51-57,共7页
China Surface Engineering
