The deformation behaviour and the nature of dislocations of the Al3Ti-base L12 alloya modified with Fe and Mn etc, were investigated. The results show that the deformation and fracture character istics are closely rel...The deformation behaviour and the nature of dislocations of the Al3Ti-base L12 alloya modified with Fe and Mn etc, were investigated. The results show that the deformation and fracture character istics are closely related to the alloy compositions. The effect of hot-working process on the room tem perature ductility is remarkable, not only resulting in an appreciable improvement of compressive properties but also showing a 0.28% plastic strain in tensile test. The SISF dissociation of a < 110>dislocations on {111} planes was found at room temperature. The determined dissociation scheme is consistent with the mechanical behaviour of these alloys in the lower temperature region.展开更多
Considering the features of martensitic transformation in Fe-Mn-Si based alloys, the Landau theory is established by introducing the density of stacking faults as a new order parameter η and the corresponding free en...Considering the features of martensitic transformation in Fe-Mn-Si based alloys, the Landau theory is established by introducing the density of stacking faults as a new order parameter η and the corresponding free energy function. By using such an order parameter, the stacking fault mechanism of the nucleation and growth for the γ(fcc) →ε(hcp) martensitic transformation can be reasonably explained, and a further detailed mechanism is proposed. The stacking faults are generated and overlapped in an irregular form at the beginning and then becoming regular to create some transition structures till a stable phase forms at a certain temperature. The importance of the interface soliton is to complete the transformations into various structures of martensite but not the twinned one. The thermodynamics of fcc→hcp transformation and those between different transition structures are described by the free energy function established in the present note.展开更多
文摘The deformation behaviour and the nature of dislocations of the Al3Ti-base L12 alloya modified with Fe and Mn etc, were investigated. The results show that the deformation and fracture character istics are closely related to the alloy compositions. The effect of hot-working process on the room tem perature ductility is remarkable, not only resulting in an appreciable improvement of compressive properties but also showing a 0.28% plastic strain in tensile test. The SISF dissociation of a < 110>dislocations on {111} planes was found at room temperature. The determined dissociation scheme is consistent with the mechanical behaviour of these alloys in the lower temperature region.
基金This work was financially supported by the National Natural Science Foundation of China (Grant No. 59671023)the Emerson Electric Corporation of U.S.A.
文摘Considering the features of martensitic transformation in Fe-Mn-Si based alloys, the Landau theory is established by introducing the density of stacking faults as a new order parameter η and the corresponding free energy function. By using such an order parameter, the stacking fault mechanism of the nucleation and growth for the γ(fcc) →ε(hcp) martensitic transformation can be reasonably explained, and a further detailed mechanism is proposed. The stacking faults are generated and overlapped in an irregular form at the beginning and then becoming regular to create some transition structures till a stable phase forms at a certain temperature. The importance of the interface soliton is to complete the transformations into various structures of martensite but not the twinned one. The thermodynamics of fcc→hcp transformation and those between different transition structures are described by the free energy function established in the present note.
