Mechanical Property And Microstructural Thermal Stability Of Cu/Cu-Zn Alloy Laminated Materials

Increasing the strength and toughness simultaneously of metal is one of the research hotspots in the study of structural materials which can relieve the demands in the lightweight and environmental protection of the industrial area.Compared with the traditional homogeneous materials,many interfaces are introduced into the multilayered material,which has a great influence on the material's strength,ductility,fatigue,thermal stability,radiation tolerance and attracts extensive attention of the researchers.Nowadays,how to increase the strength and ductility of laminated materials is mainly according to the strength criterion.In another word,increasing the difference of strength between the components can promote the non-homogenous deformation which can contribute to the accumulation of geometrically necessary dislocation.However,except the strength,the non-homogenous deformation also relates to the work hardening or ductility.Work hardening capability reflects the uniform plastic deformability or deformation stability and is a synthetic effect of the strength and ductility.But the influence law of the work hardening on the mechanical property of laminated materials is rare to reported.Besides,the interface also affects the thermal stability of laminated materials.The stable phase interface and straight geometric configuration can raise the thermal stability of laminated materials whose compositions are insoluble.But there are few researches studying the thermal stability of laminated materials whose compositions are mutually soluble.In this work,a series of homogeneous and laminated materials was prepared by cold rolling,accumulated rolled bonding(ARB),annealing and so on.And the influence of work hardening capability on the mechanical property of laminated materials and the impact of the interface on the thermal stability were studied.The main results are as follows.1)The influence of the Zn's content on the Cu-Zn alloys' thermal stability was studied in this work.The result indicates that with the increasing of the Zn content,the thermal stability of the Cu,H96(Cu-4 wt%Zn),H90(Cu-10 wt%Zn)and H68(Cu-32 wt%Zn)increases first followed by a decreasing.More specifically,as the content of Zn increases,solution strengthening becomes stronger and the stacking fault energy declines accordingly.Since the solute atoms contribute to the thermal stability but the decreasing of stacking fault energy is detrimental,the thermal stability shows a turning point due to the competition of these two factors.2)To study the impact of the interface on the thermal stability of laminated materials,The Cu/H96 laminated composite materials with different interface spacing(from 19 to 300?m)were prepared by accumulated rolled bonding(ARB)and annealed at 533 K for 2 h.The results show that with the decreasing of interface spacing,the recrystallization ratio of the materials increases which indicates the decline of the thermal stability.After the rolling,the interfaces possess excessive distortion energy which drives the recrystallization and results in the decreasing of the thermal stability.3)To investigate of the effect of the components' work hardening discrepancy on the laminated materials' mechanical property,two kinds of heterogeneous laminated materials(annealed Cu/H96 and Cu/H68)with different interface spacing were prepared by ARB.For the annealed Cu/H96 laminated material,the copper layer has a good work hardening ability but the H96 layer is on the contrary.There is a big difference of the work hardening ability between the two components.For the annealed Cu/H68 laminated material,both the two layers have a good work hardening ability.The difference of the work hardening ability between two components is smaller than the Cu/H96.Compared the yield strength of these two kinds of laminated materials,larger work hardening discrepancy exhibits a more pronounced strengthening.Because of the large difference in work hardening between components,the laminate exhibits more apparent strain partition and the interface can accumulate more GNDs.Obviously,abundant GNDs can raise the yield strength of the laminated materials.4)For further improving the mechanical property of laminated materials,the heterogeneous laminated materials consisting four components(Cu,H96(Cu-4 wt%Zn),H90(Cu-10 wt%Zn)and H68(Cu-32 wt%Zn))with different laminated thickness(19?m and 75?m)were fabricated by ARB and annealing.The result indicates that with the decreasing of the layer thickness,the recrystallization increases.And the ductility of the material increases with the yield strength remaining constant.In short,the strength-ductility synergy of the layered materials becomes better.It originates from the increment of the strain gradient in material which is of benefit to the accumulation of GNDs.