摘要 : The concept of gradient composite amorphous filler metal (GAFM) was utilized to solve the scientific problem of low strength caused by excessive Ti-containing brittle-hard intermetallic compounds (IMCs) generated in Ni/TiAl brazed... 展开 The concept of gradient composite amorphous filler metal (GAFM) was utilized to solve the scientific problem of low strength caused by excessive Ti-containing brittle-hard intermetallic compounds (IMCs) generated in Ni/TiAl brazed joints through interfacial hysteresis reaction. Based on the cluster-plus-glue-atom model, the GAFMs (Zr_(25)Ti_(21.25)Ni_(25)Cu_(18.75)/Zr_(31.25-X)V_XCu_(50)Ni_(18.75)) were designed for vacuum brazing of K4169 alloy with TiAl intermetallic. And the shear strength of the joint brazed with (Ti_(21.25)Zr_(25)Ni_(25)Cu_(18.75)/Zr_(25)V_(6.25)Cu_(50)Ni_(18.75)) GAFM reached 344 MPa. The relation between grain boundary, solution, dislocation and strength was established. The cracks initiated from the (Ti,Zr)(Ni,Cu)+(Cr,Fe,Ni) brittle-hard phase and the plastic-tough phase (Zr,Ti)(Ni,Cu) interface in Zone Ⅱ with (Ti_(21.25)Zr_(25)Ni_(25)Cu_(18.75)/Zr_(31.25-X)V_XCu_(50)Ni_(18.75)) GAFMs at 1040 ℃/10 min, and then extended to the (Ti,Zr)(Al,Ni,Cu)_(3[010])/(Ti,Zr)(Ni,Cu,Al)_(3[0-10]) non-coherent interface. To regulate the distribution of the plastic-tough phase in Zone Ⅱ, raising brazing temperature could promote the dissolution of Zone Ⅰ into Zone Ⅱ. The addition of V to the GAFMs, ε_G and ε_α mismatches increased and prompted the Ni_(ss[00-1])+TiAl_([010]) phase, (Cr,Fe,Ni)_(ss[00-1]) phase with a-value lattice distortion of 21.38%, (Ni,Cr,Fe) and ZrNi_(3[0-2-1]) grains refinement in Zone Ⅱ, where K*_(IC)/K_(IC)＞1, the brazed joint strengthening effect was enhanced. The columnar grains were transformed into grains with reticulated cladding characteristics. The percentage of sub-structured grains increased from 46.6% to 56.3%, and the percentage of HAGBs rose to 84.7%, which inhibited dislocation migration. Therefore, the ZrNi_3 plastic-tough phase, prohibited the expansion of the major crack generated from the (Cr,Fe,Ni) brittle-hard phase. The major crack extended to the Ti(Ni,Cu,Al)_3 [1-10]/Ti(Al,Cu, Ni)_(2[0-10]) semi-coherent interface and then to the TiAl substrate, resulting in a zigzag crack expansion. 收起