The rupture behavior of a cast Ni-base superalloy M963 at high temperature has been investi- gated. The microstructure examination shows that there exists a large amount of the carbide and γ-γ' eutectic, which i...The rupture behavior of a cast Ni-base superalloy M963 at high temperature has been investi- gated. The microstructure examination shows that there exists a large amount of the carbide and γ-γ' eutectic, which is very harmful to the mechanical properties of M963 superalloy. The tensile strength of M963 superalloy both at room temperature and at high temperatures is higher than that of K17G alloy, but the tensile ductility of the former is much lower than that of the latter. In tensile fracture process with the high strain rate, the open carbides are the initiation site and the carbide/matrix interface is the propagation path of cracks. But in fracture process with the low strain rate, the carbide/matrix interface and cast microvoids are the initiation sites, and the carbide/matrix interface is the propagation path of cracks. The effective ways to improve ductility of M963 superalloy are also suggested.展开更多
FeAl composites with 21, 37 and 50 wt pct Fe3AlC0.5 were fabricated by a self-propagating high temperature synthesis （SHS） casting. Phases and microstructures were analyzed by X-ray diffraction （XRD） and scanning ...FeAl composites with 21, 37 and 50 wt pct Fe3AlC0.5 were fabricated by a self-propagating high temperature synthesis （SHS） casting. Phases and microstructures were analyzed by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. Microhardness and bending strength of the composites were measured. The composites with 21 and 50 wt pct Fe3AlC0.5 mainly consisted of FeAl and FesAlC0.5 phases, whereas the composite with 37 wt pct Fe3AlC0.5 was composed of FeAl, Fe3AlC0.5 and graphite phases. The bonding of the reinforcement and the matrix was good. Hardness and bending strength of the composite with 37 wt pct Fe3AlC0.5 was lower than those of the 21 and 50 wt pct composites owing to the presence of the soft graphite phase.展开更多
An ultrafine grained Fe-40Al intermetallic compound is fabricated by a self- propagating high temperature synthesis （SHS） casting. The XRD result shows that the Fe-40Al intermetallic compound consists of the B2 FeAl...An ultrafine grained Fe-40Al intermetallic compound is fabricated by a self- propagating high temperature synthesis （SHS） casting. The XRD result shows that the Fe-40Al intermetallic compound consists of the B2 FeAl phase. The Fe-40Al intermetallic compound presents ultrafine grain size in the range of 100-600 rim, leading from the high nucleation rate and the low growth rate. The Fe-40Al intermetallic compound exhibits high hardness （3.4 GPa） and high bending strength （830 MPa） and high compressive strength （2700 MPa）, which originate from the ultrafine-structure in the material. The effect of the load on dry-sliding wear rate of the material against AISI52100 steel was investigated. The wear rate increases with the increase of normal load. The dominated weax mechanism is microfracture.展开更多
基金supported by the Postdoctoral Science Foundation of China
文摘The rupture behavior of a cast Ni-base superalloy M963 at high temperature has been investi- gated. The microstructure examination shows that there exists a large amount of the carbide and γ-γ' eutectic, which is very harmful to the mechanical properties of M963 superalloy. The tensile strength of M963 superalloy both at room temperature and at high temperatures is higher than that of K17G alloy, but the tensile ductility of the former is much lower than that of the latter. In tensile fracture process with the high strain rate, the open carbides are the initiation site and the carbide/matrix interface is the propagation path of cracks. But in fracture process with the low strain rate, the carbide/matrix interface and cast microvoids are the initiation sites, and the carbide/matrix interface is the propagation path of cracks. The effective ways to improve ductility of M963 superalloy are also suggested.
基金the National Natural Science Foundation of China(No.50801064)the National 973 Project of China(NO.2007CB607601)the National 863 Project of China(No.2006AA03A219)for financial support.
文摘FeAl composites with 21, 37 and 50 wt pct Fe3AlC0.5 were fabricated by a self-propagating high temperature synthesis （SHS） casting. Phases and microstructures were analyzed by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. Microhardness and bending strength of the composites were measured. The composites with 21 and 50 wt pct Fe3AlC0.5 mainly consisted of FeAl and FesAlC0.5 phases, whereas the composite with 37 wt pct Fe3AlC0.5 was composed of FeAl, Fe3AlC0.5 and graphite phases. The bonding of the reinforcement and the matrix was good. Hardness and bending strength of the composite with 37 wt pct Fe3AlC0.5 was lower than those of the 21 and 50 wt pct composites owing to the presence of the soft graphite phase.
基金supported by the National Natural Science Foundation of China (No50801064)the National Basic Research Program of China(No2007CB607601)
文摘An ultrafine grained Fe-40Al intermetallic compound is fabricated by a self- propagating high temperature synthesis （SHS） casting. The XRD result shows that the Fe-40Al intermetallic compound consists of the B2 FeAl phase. The Fe-40Al intermetallic compound presents ultrafine grain size in the range of 100-600 rim, leading from the high nucleation rate and the low growth rate. The Fe-40Al intermetallic compound exhibits high hardness （3.4 GPa） and high bending strength （830 MPa） and high compressive strength （2700 MPa）, which originate from the ultrafine-structure in the material. The effect of the load on dry-sliding wear rate of the material against AISI52100 steel was investigated. The wear rate increases with the increase of normal load. The dominated weax mechanism is microfracture.
