激光熔覆TiC_p/Ni合金涂层中界面结构及界面硬度与弹性模量分布

INTERFACE STRUCTURE AND DISTRIBUTIONS OF HARDNESS ADN MODULUS NEAR INTERFACE IN TiCp/Ni LASER CLAD COATINGS

利用激光熔覆制备了两类ＴｉＣｐ／Ｎｉ合金涂层与自生ＴｉＣｐ涂层不同，在添加ＴｉＣｐ涂层中，ＴｉＣｐ与基体界面处观察到 ＴｉＣ外延生长及 ＣｒＢ．相利用纳米硬度仪研究了涂层中 ＴｉＣｐ与基体的界面硬度 Ｈ及弹性模量 Ｅ的分布添加 ＴｉＣｐ与基体相界面加载的曲线存在位移突进（ｐｏｐ－ｉｎ）现象；原位ＴｉＣｐ界面附近加载曲线不存在ｐｐｐ－ｉｎ现象．原位ＴｉＣｐ相界面附近 Ｈ及 Ｅ较高并呈现连续梯度分布特征，表明原位ＴｉＣｐ界面具有高的刚度与强韧性．

Additional and in situ titanium carbide particle (TiCp) reinforced Ni based alloy composite coatings are synthesized by laser cladding method. The former comes from the TiCp pre-coated on the sample whereas the latter from in site reaction between titanium and graphite in the molten pool during laser irradiation. ATEM observation shows the existence of the epitaxial growth of TiC and the precipitation of CrB around interfaces of additional TiCp and the corresponding loading curve obtained by nanoindenter presents pop-in phenomena due to the plastic deformation of the crack formation or debounding of TiCp from the matrix. For the in situ TiCp interface no pop-in mark appears. The interface formed in situ possesses high fracture toughness, and much higher hardness and modulus than those of additional TiCp interface. The distribution of hardness and modulus near in situ TiCp interface has gradient characteristics.