The wettability and interfacial reactions of four kinds of PdNi-based brazing fillers on C-C composite were studied with the sessile drop method.The results showed that the wettability of these brazing fillers was imp...The wettability and interfacial reactions of four kinds of PdNi-based brazing fillers on C-C composite were studied with the sessile drop method.The results showed that the wettability of these brazing fillers was improved with the increase of Cr content. Cr distributed at the interface of brazing filler/C-C composite and the formation of Cr23C6 phase was speculated.In the interface between Ni-33Cr-24Pd-4Si brazing filler and C-C composite,element Cr reacted with C-C to form Cr-C reaction layer.Pd together with Si participated in the interfacial reactions and formed Pd2Si and Pd3Si phases.Furthermore,in this reaction zone,the residual brazing alloy became Ni-rich and Pd-depleted.展开更多
Transient liquid phase (TLP) bonding technique was used in joining IC6 alloy, a newly developed Ni 3Al based intermetallic material. Studies were focused on the borides at the interfacial zone, which were formed throu...Transient liquid phase (TLP) bonding technique was used in joining IC6 alloy, a newly developed Ni 3Al based intermetallic material. Studies were focused on the borides at the interfacial zone, which were formed through the diffusion of boron from the interlayer into the base metal during the bonding process. The morphology and microstructure of the borides were investigated, as well as their growth mechanism and microstructure evolution with increasing holding time. Both the needle like and the blocky borides were testified by EDS and TEM as Mo 2NiB 2, with (110) and (211) as interfacial planes. The results show that the borides have some orientation relationship with that of the base metal, that is (211) borides ∥(111) substrate ,〈111〉 borides ∥〈123〉 substrate . The growth of the borides is controlled by long range diffusion of solute atoms. The borides are always enveloped by γ ′ Ni 3 (Al, Mo) films, which would influence the growth behavior of the borides greatly.展开更多
In the present work, the dissimilar joining of a Ti3Al-based alloy to a Ni-based superalloy was attempted by gas tungsten arc （GTA） welding technology. Sound joints were successfully achieved by using a Cu-Ni alloy ...In the present work, the dissimilar joining of a Ti3Al-based alloy to a Ni-based superalloy was attempted by gas tungsten arc （GTA） welding technology. Sound joints were successfully achieved by using a Cu-Ni alloy as filler material. According to X-ray energy dispersive spectroscopy and X-ray diffraction analysis results three transitional layers at the weld/Ti3Al interface were verified as follows： Ti2AlNb phase dissolved with Cu and Ni; Al（Cu,Ni）2Ti, （Cu,Ni）2Ti and （Nb, Ti） solid solution; Cu-rich phase and a complex multi-element phase. The In718/weld interface is characterized by solid solutions of Ni, Cu, Cr, Fe and Nb. The average tensile strength of the as-welded joints at room temperature is 163 MPa, and after a post-weld heat treatment it is increased slightly to 177 MPa. The fracture occurred at the surfacial layer of the joined Ti3Al base alloy, indicating that the Ti2AINb layer dissolved with Cu and Ni is the weak link of the Ti3Al/In718 joint.展开更多
基金Projects(59905022,50475160)supported by the National Natural Science Foundation of China
文摘The wettability and interfacial reactions of four kinds of PdNi-based brazing fillers on C-C composite were studied with the sessile drop method.The results showed that the wettability of these brazing fillers was improved with the increase of Cr content. Cr distributed at the interface of brazing filler/C-C composite and the formation of Cr23C6 phase was speculated.In the interface between Ni-33Cr-24Pd-4Si brazing filler and C-C composite,element Cr reacted with C-C to form Cr-C reaction layer.Pd together with Si participated in the interfacial reactions and formed Pd2Si and Pd3Si phases.Furthermore,in this reaction zone,the residual brazing alloy became Ni-rich and Pd-depleted.
文摘Transient liquid phase (TLP) bonding technique was used in joining IC6 alloy, a newly developed Ni 3Al based intermetallic material. Studies were focused on the borides at the interfacial zone, which were formed through the diffusion of boron from the interlayer into the base metal during the bonding process. The morphology and microstructure of the borides were investigated, as well as their growth mechanism and microstructure evolution with increasing holding time. Both the needle like and the blocky borides were testified by EDS and TEM as Mo 2NiB 2, with (110) and (211) as interfacial planes. The results show that the borides have some orientation relationship with that of the base metal, that is (211) borides ∥(111) substrate ,〈111〉 borides ∥〈123〉 substrate . The growth of the borides is controlled by long range diffusion of solute atoms. The borides are always enveloped by γ ′ Ni 3 (Al, Mo) films, which would influence the growth behavior of the borides greatly.
文摘In the present work, the dissimilar joining of a Ti3Al-based alloy to a Ni-based superalloy was attempted by gas tungsten arc （GTA） welding technology. Sound joints were successfully achieved by using a Cu-Ni alloy as filler material. According to X-ray energy dispersive spectroscopy and X-ray diffraction analysis results three transitional layers at the weld/Ti3Al interface were verified as follows： Ti2AlNb phase dissolved with Cu and Ni; Al（Cu,Ni）2Ti, （Cu,Ni）2Ti and （Nb, Ti） solid solution; Cu-rich phase and a complex multi-element phase. The In718/weld interface is characterized by solid solutions of Ni, Cu, Cr, Fe and Nb. The average tensile strength of the as-welded joints at room temperature is 163 MPa, and after a post-weld heat treatment it is increased slightly to 177 MPa. The fracture occurred at the surfacial layer of the joined Ti3Al base alloy, indicating that the Ti2AINb layer dissolved with Cu and Ni is the weak link of the Ti3Al/In718 joint.
