Research For Friction And Wear Of Ni Based Superalloy And The MCrAlYSi Coating Deposite On The Superalloy

Wear was one of the main failure mode of nickel-based superalloy during the serving process. The superalloy have excellent friction and wear properties in high temperature, but these performance were limited in room temperature and medium temperature stage. The MCrAlYSi(M for Ni, Co or Ni + Co) coating technology have been widely used for surface modification of nickel base superalloy material. And so three representative superalloy, where were K417 G ordinary casting superalloy,directional solidification superalloy DZ417 G and single crystal superalloy DD417 G alloy, and MCrAlYSi coatings, where were the NiCrAlYSi coating deposited by arc ion plating(AIP) and laser cladding repectivily, and the NiCoCrAlYSi coating deposited by laser cladding, were selected for investigating there friction and wear properties in this study. The enviromental embrittlement sensitivity of the superalloy and coatings were determined by energetical analysis and calculated. The microstructural of superalloy and coatings were observed and analyzed by SEM/EDS,X-ray diffraction and other testing technology. The main results are as follows:(1) The friction and wear properties of K417 G superalloy was better than DZ417 G and DD417 G superalloy. The worn of the three kinds of superalloy was affected by the interaction of surface environment embrittlement and fatigue delamination in the subsurface stratum, accompanied by the adhesive and abrasive wear. The enviromental embrittlement act on the worn surface gradually during the process of wear.(2) It has been found that the ? and ?? phase indwell in the AIP NiCrAlYSi coating, laser cladding NiCrAlYSi coating and laser cladding NiCoCrAlYSi coating.The enviromental embrittlement still generated during the process of wear. The worn surface showed obvious peeling and crack characteristics. The enviromental embrittlement was restrained as the increasing of temperature.(3) The environmental sensitivity and the cotent of Al or Ti were high in the K417 G alloy and Ni(Co)CrAlYSi coating. And they would reacted with water vapor generation hydrogen atom easily during the process of wear, resultting in theenviromental embrittlement. The results also showed that the enviromental embrittlement of superalloy and coatings are depended upon the water vapor cotent in environment. And it would be improved when the relative humidity reduced to 25%.The superalloy and coatings are insensitive to the hydrogen molecular, and could not produce enviromental embrittlement in hydrogen atmosphere. The oxgen has an important effect on the friction and wear properties of K417 G superalloy and NiCoCrAlYSi coating. The friction and wear properties of the superalloy and coating in the air are better than that in oxgen-free atmosphere such as argon, hydrogen and carbon dioxide.