The effect of strain rate and deformation temperature on theα→βphase transformation in 47Zr-45Ti-5Al-3V alloy with an initial widmanstattenαstructure was investigated.At the deformation temperature of 550°C,t...The effect of strain rate and deformation temperature on theα→βphase transformation in 47Zr-45Ti-5Al-3V alloy with an initial widmanstattenαstructure was investigated.At the deformation temperature of 550°C,the volume fraction ofαphase decreased with increasing strain rate.At 600 and 650°C,the volume fraction ofαphase firstly increased to a maximum value with increasing strain rate from 1×10-3 to 1×10-2 s-1,and then decreased.At 700°C,the microstructure consisted of singleβphase.At a given strain rate,the volume fraction ofαphase decreased with increasing deformation temperature.With decreasing strain rate and increasing deformation temperature,the volume fraction and size of globularαphase increased.At 650°C and 1×10-3 s-1,the lamellarαphase was fully globularized.The variation in the volume fraction and morphology ofαphase with strain rate and deformation temperature significantly affected the hardness of 47Zr-45Ti-5Al-3V alloy.展开更多
The structure change of α2/γ interface in a Ti-45Al-10Nb alloy induced by hot deformation was investigated by conventional and high-resolution transmission eIectron microscopy. Two types of hot deformation induced s...The structure change of α2/γ interface in a Ti-45Al-10Nb alloy induced by hot deformation was investigated by conventional and high-resolution transmission eIectron microscopy. Two types of hot deformation induced special α2/γ intedeces, coherent intedeces with high density of ledges and semi-coherent α2/γ intedeces were found to be due to the absorption of mobile dislocations into the α2/γ inteface. For the misoriented semi-coherent α2/γ interfaces, the densities of dislocation ledges increase with the misoriented angle between (111)γ and (0001)α2 planes, and 1/3[111] Frank partial dislocations were involved in the dislocation ledges. Formation mechanism of these deformation-induced α2/γ interfaces was discussed to be related to the role of α2/γ interface5 adjusting the deformation as a dislocation sink absorbing the slipping dislocations in the γ phase展开更多
Ti-47Al-2Nb-2Cr-0.15B(mole fraction,%)alloy was vacuum brazed with amorphous and crystalline Ti.25Zr-12.5Cu-12.5Ni-3.0Co-2.0Mo(mass fraction,%)filler alloys,and the melting,spreading and gap filling behaviors of the a...Ti-47Al-2Nb-2Cr-0.15B(mole fraction,%)alloy was vacuum brazed with amorphous and crystalline Ti.25Zr-12.5Cu-12.5Ni-3.0Co-2.0Mo(mass fraction,%)filler alloys,and the melting,spreading and gap filling behaviors of the amorphous and crystalline filler alloys as well as the joints brazed with them were investigated in details.Results showed that the amorphous filler alloy possessed narrower melting temperature interval,lower liquidus temperature and melting active energy compared with the crystalline filler alloy,and it also exhibited better brazeability on the surface of the Ti.47Al.2Nb.2Cr.0.15B alloy.The TiAl joints brazed with crystalline and amorphous filler alloys were composed of two interfacial reaction layers and a central brazed layer.Under the same conditions,the tensile strength of the joint brazed with the amorphous filler alloy was always higher than that with the crystalline filler alloy.The maxmium tensile strength of the joint brazed at 1273 K with the amorphous filler alloy reached 254 MPa.展开更多
The characteristics of fatigue crack initiation in Ti-5AI-4Sn-2Zr1Mo-O.7Nd-O.25Si alloy wereStudied. Two modes Of fatigue crack initiation were found. The Nd-rich phase particles displaybetter resistance to fatigue cr...The characteristics of fatigue crack initiation in Ti-5AI-4Sn-2Zr1Mo-O.7Nd-O.25Si alloy wereStudied. Two modes Of fatigue crack initiation were found. The Nd-rich phase particles displaybetter resistance to fatigue crack initiation than the matrix at lower stress.展开更多
基金Project(201629) supported by the Scientific Research Foundation for Introduced Talent of Guizhou University,ChinaProjects(20164014,20165654) supported by the Hundred-level Innovative Talents Project of Guizhou Province,ChinaProject(20146013) supported by the Science and Technology of Guizhou Province,China
文摘The effect of strain rate and deformation temperature on theα→βphase transformation in 47Zr-45Ti-5Al-3V alloy with an initial widmanstattenαstructure was investigated.At the deformation temperature of 550°C,the volume fraction ofαphase decreased with increasing strain rate.At 600 and 650°C,the volume fraction ofαphase firstly increased to a maximum value with increasing strain rate from 1×10-3 to 1×10-2 s-1,and then decreased.At 700°C,the microstructure consisted of singleβphase.At a given strain rate,the volume fraction ofαphase decreased with increasing deformation temperature.With decreasing strain rate and increasing deformation temperature,the volume fraction and size of globularαphase increased.At 650°C and 1×10-3 s-1,the lamellarαphase was fully globularized.The variation in the volume fraction and morphology ofαphase with strain rate and deformation temperature significantly affected the hardness of 47Zr-45Ti-5Al-3V alloy.
文摘The structure change of α2/γ interface in a Ti-45Al-10Nb alloy induced by hot deformation was investigated by conventional and high-resolution transmission eIectron microscopy. Two types of hot deformation induced special α2/γ intedeces, coherent intedeces with high density of ledges and semi-coherent α2/γ intedeces were found to be due to the absorption of mobile dislocations into the α2/γ inteface. For the misoriented semi-coherent α2/γ interfaces, the densities of dislocation ledges increase with the misoriented angle between (111)γ and (0001)α2 planes, and 1/3[111] Frank partial dislocations were involved in the dislocation ledges. Formation mechanism of these deformation-induced α2/γ interfaces was discussed to be related to the role of α2/γ interface5 adjusting the deformation as a dislocation sink absorbing the slipping dislocations in the γ phase
基金Foundation item:Project(51865012)supported by the National Natural Science Foundation of ChinaProject(2016005)supported by the Open Foundation of National Engineering Research Center of Near-net-shape Forming for Metallic Materials,China+2 种基金Project(GJJ170372)supported by the Science Foundation of Educational Department of Jiangxi Province,ChinaProject(JCKY2016603C003)supported by the GF Basic Research Project,ChinaProject(JPPT125GH038)supported by the Research Project of Special Furnishment and Part,China
文摘Ti-47Al-2Nb-2Cr-0.15B(mole fraction,%)alloy was vacuum brazed with amorphous and crystalline Ti.25Zr-12.5Cu-12.5Ni-3.0Co-2.0Mo(mass fraction,%)filler alloys,and the melting,spreading and gap filling behaviors of the amorphous and crystalline filler alloys as well as the joints brazed with them were investigated in details.Results showed that the amorphous filler alloy possessed narrower melting temperature interval,lower liquidus temperature and melting active energy compared with the crystalline filler alloy,and it also exhibited better brazeability on the surface of the Ti.47Al.2Nb.2Cr.0.15B alloy.The TiAl joints brazed with crystalline and amorphous filler alloys were composed of two interfacial reaction layers and a central brazed layer.Under the same conditions,the tensile strength of the joint brazed with the amorphous filler alloy was always higher than that with the crystalline filler alloy.The maxmium tensile strength of the joint brazed at 1273 K with the amorphous filler alloy reached 254 MPa.
文摘The characteristics of fatigue crack initiation in Ti-5AI-4Sn-2Zr1Mo-O.7Nd-O.25Si alloy wereStudied. Two modes Of fatigue crack initiation were found. The Nd-rich phase particles displaybetter resistance to fatigue crack initiation than the matrix at lower stress.
