The bainitic transformation in a Cu-Zn-Al-Mn alloy has been examined with TEM.The re- sults show that the stacking faults and also the bainitic midrib are found at the beginning of bainite formation in the alloy.The s...The bainitic transformation in a Cu-Zn-Al-Mn alloy has been examined with TEM.The re- sults show that the stacking faults and also the bainitic midrib are found at the beginning of bainite formation in the alloy.The stacking fault planes can pass continuously through the midrib in bainite.The growth ledges occur at the broad faces and rims of bainite.The broad and narrow faces of th ledges are parallel to the fault plane and habit plane respectively.Both their Miller indices are {110}_(B2).The moving direction of ledges is parallel to the fault plane. It may be deduced that the bainite in alloy are initially formed by shear and the process of growth are go verned by propagation o f fault planes.展开更多
TTT diagrams and kinetics curves of bainite formation through up quenching from martensitic slate and of dilatometry and cooling from high temperature parent phase in Cu-Zn-Al alloys are established by ments of dilato...TTT diagrams and kinetics curves of bainite formation through up quenching from martensitic slate and of dilatometry and cooling from high temperature parent phase in Cu-Zn-Al alloys are established by ments of dilatometry and metallographic inspection.Experimental results show that the kinetics characteristics of bainite formation obey the Austin-Rickett Equation with n=2.25 for up-quenched specimens and n=1.80 for specimens cooled from high temperature,and the activation energy of bainite formation is about.110 kJ/mol,corresponding to that ofthe diffusion of solute atoms.展开更多
The ordering of bainite is studied and compared with that of martensite in a Cu-20Zn-6Al(wt—％) alloy by X-ray analysis. Experilnental results show that in contrast with the diffraction pattern for 9R or 18R martensi...The ordering of bainite is studied and compared with that of martensite in a Cu-20Zn-6Al(wt—％) alloy by X-ray analysis. Experilnental results show that in contrast with the diffraction pattern for 9R or 18R martensite, in which the (115) diffraction peak is distinguishable from the (■ 0 5), and the (1 2 10) from the (2 0 10), the (1 1 5) and (■ 0 5) or the (1 2 10) and (■0 10) diffraction peaks in the bainites formed from high temperature B2 or low temperature L2 parent phase overlap, and these phenomena do not change after prolonged aging or slow-cooling. The bainite structure is quite different from that of the martensite, i. e., the inheritance of the ordering of the parent phase would not occur, during bainite formation.展开更多
The bainitic transformation mechanism is one of the controversial issues in solid phase transformations on which sharp arguments have lasted for a long time. A lot of research work on this mechanism has been done by b...The bainitic transformation mechanism is one of the controversial issues in solid phase transformations on which sharp arguments have lasted for a long time. A lot of research work on this mechanism has been done by both the shear and diffusion schools. Results from these two schools have many differences and the viewpoints on them are different essentially as展开更多
The crystallographic nature of initial isothermal phase transformation in Cu-26Zn-4Al (wt-％) was investigated. The kinetic transforma- tion curve, morphology, crystal structure, substructure, orientation relationship...The crystallographic nature of initial isothermal phase transformation in Cu-26Zn-4Al (wt-％) was investigated. The kinetic transforma- tion curve, morphology, crystal structure, substructure, orientation relationship and twin relationship of bainite plates have been studied by means of optical and transmission electron microscopy. The experimental results showed that the characteristics of initial 8→bainite transformation are not exactly consistent with that found in martensite transformation, for example, orientation relationship between matrix and bainite does not exist in martensite transformation.展开更多
The bainite structure in a Cu-Zn-A1 alloy related to the reverse shape memory effect has been observed by means of TEM.The reverse memory effect may be improved by up to one order of magnitude under applied constraint...The bainite structure in a Cu-Zn-A1 alloy related to the reverse shape memory effect has been observed by means of TEM.The reverse memory effect may be improved by up to one order of magnitude under applied constraint stress.The widespread propagation of bainite was confirmed to be the diffusion controlled shear process by the parabolic configuration of side interface of bainite plate and the twisting of intersected bainite plates.展开更多
文摘The bainitic transformation in a Cu-Zn-Al-Mn alloy has been examined with TEM.The re- sults show that the stacking faults and also the bainitic midrib are found at the beginning of bainite formation in the alloy.The stacking fault planes can pass continuously through the midrib in bainite.The growth ledges occur at the broad faces and rims of bainite.The broad and narrow faces of th ledges are parallel to the fault plane and habit plane respectively.Both their Miller indices are {110}_(B2).The moving direction of ledges is parallel to the fault plane. It may be deduced that the bainite in alloy are initially formed by shear and the process of growth are go verned by propagation o f fault planes.
文摘TTT diagrams and kinetics curves of bainite formation through up quenching from martensitic slate and of dilatometry and cooling from high temperature parent phase in Cu-Zn-Al alloys are established by ments of dilatometry and metallographic inspection.Experimental results show that the kinetics characteristics of bainite formation obey the Austin-Rickett Equation with n=2.25 for up-quenched specimens and n=1.80 for specimens cooled from high temperature,and the activation energy of bainite formation is about.110 kJ/mol,corresponding to that ofthe diffusion of solute atoms.
文摘The ordering of bainite is studied and compared with that of martensite in a Cu-20Zn-6Al(wt—％) alloy by X-ray analysis. Experilnental results show that in contrast with the diffraction pattern for 9R or 18R martensite, in which the (115) diffraction peak is distinguishable from the (■ 0 5), and the (1 2 10) from the (2 0 10), the (1 1 5) and (■ 0 5) or the (1 2 10) and (■0 10) diffraction peaks in the bainites formed from high temperature B2 or low temperature L2 parent phase overlap, and these phenomena do not change after prolonged aging or slow-cooling. The bainite structure is quite different from that of the martensite, i. e., the inheritance of the ordering of the parent phase would not occur, during bainite formation.
文摘The bainitic transformation mechanism is one of the controversial issues in solid phase transformations on which sharp arguments have lasted for a long time. A lot of research work on this mechanism has been done by both the shear and diffusion schools. Results from these two schools have many differences and the viewpoints on them are different essentially as
文摘The crystallographic nature of initial isothermal phase transformation in Cu-26Zn-4Al (wt-％) was investigated. The kinetic transforma- tion curve, morphology, crystal structure, substructure, orientation relationship and twin relationship of bainite plates have been studied by means of optical and transmission electron microscopy. The experimental results showed that the characteristics of initial 8→bainite transformation are not exactly consistent with that found in martensite transformation, for example, orientation relationship between matrix and bainite does not exist in martensite transformation.
文摘The bainite structure in a Cu-Zn-A1 alloy related to the reverse shape memory effect has been observed by means of TEM.The reverse memory effect may be improved by up to one order of magnitude under applied constraint stress.The widespread propagation of bainite was confirmed to be the diffusion controlled shear process by the parabolic configuration of side interface of bainite plate and the twisting of intersected bainite plates.
