摘要
采用X射线衍射、SEM、EDXS及显微硬度等方法,研究了光束堆焊Ni,Al混合粉末制备的金属间化合物涂层的成形和微观组织特征。结果表明,堆焊层的成形与堆焊材料的比热容量和熔点有关。采用Al含量(原子分数)高于50％或不超过25％的堆焊材料,均可获得成形良好的光束堆焊层,但Al含量过高将使堆焊金属的致密度降低。当堆焊材料中Al含量为50％—75％时,堆焊层全部由金属间化合物(Al_(1.1)Ni_(0.9),Al_3Ni_2和Al_3Ni)组成;当采用富Ni堆焊材料(不超过25％Al)时,堆焊层中将析出较多的γ—Ni固溶体,得到由γ—Ni和Ni_3Al金属间化合物组成的显微组织;而采用富Al堆焊材料(80％Al)将导致堆焊层中析出大量α—Al,其显微组织为在α—Al+(α—Al+Al_3Ni)亚共晶基底上分布有Al_3Ni_2金属间化合物相。
The formation and microstructure of intermetallic surfacing layers acquired by light beam heating Ni and Al mixed powder were investigated by means of X-ray diffraction, SEM, EDXS and microhardness. The results show that the formation of surfacing layers is related to the heat capacity and melting point of surfacing materials. When the surfacing materials with more than 50%Al (atomic fraction) or not more than 25%Al are used, the surfacing layers with good formation can be obtained. However, too high Al content results in the decrease of the densification of surfacing layer. When the surfacing materials contain 50%-75%Al, the surfacing layers entirely consist of NiAl intermetallics (Al1.1Ni0.9, Al3Ni2, Al3Ni). When the surfacing material is rich in Ni (not more than 25%Al), the microstructure is composed of gamma-Ni matrix and Ni3Al intermetallic. Adopting the surfacing material rich in Al (80%Al) leads to the precipitation of a lot of alpha-Al, and the microstructure consists of Al3Ni2 intermetallic precipitated on hypoeutectic matrix composed of the primary alpha-Al and the eutectic of alpha-Al+Al3Ni.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2004年第5期483-488,共6页
Acta Metallurgica Sinica
基金
国家自然科学基金 50275082
