热处理对机械合金化Ni/Ti冷喷涂层金属间化合物形成的影响
Effect of annealing treamenton formation of intermetallic phase in cold-sprayed Ni/Ti mechanical alloying coating
-
摘要: 选择了三种球磨时间制备的Ni/Ti机械合金化粉末,通过冷喷涂制备了不同结构的Ni/Ti涂层.涂层组织结构采用扫描电镜(SEM)和X射线衍射(XRD)进行了表征分析.试验发现,随着粉末球磨时间的增加,热处理后的冷喷涂合金转变为金属间化合物的温度下降,涂层的组成相由Ni3Ti,B2-NiTi和Ti2Ni逐渐变成Ni3Ti和Ti2Ni;随着热处理温度的增加,涂层组织中不同成分的金属间化合物的相对量会发生一定改变.结果表明,热处理过程中形成的B2-NiTi金属间化合物在冷却时表现出较高的稳定性.Abstract: Three kinds of Ni/Ti mechanical alloying powder prepared by mechanical alloying at differentmilling time are employed o from Ni/Ti coatings by cold spraying.The micro-structures of the coatings annealing under different conditions are characterized by scanning electron microscopy(SEM) and X-ray diffraction(XRD).It is found that the formation temperature of Ni-Ti inter metallics from the cold-sprayed alloy is decreased with increasing ball milling time for powder preparation.Moreover,the phase constitutions change from Ni3Ti,B2-NiTi and Ti2Ni to Ni3Ti and Ti2Ni.The increase of annealing temperature only leads to the change of the relative content of different intermetallic phases in the coating.The results show that in termetallic B2-NiTi phase formed during annealing exhibits good stability during cooling process.