In order to better understand the relation between grain boundary characteristic distribution （GBCD） and the brittle cracking of ferritic stainless steel, the GBCD, impact test and bend test were investigated using ...In order to better understand the relation between grain boundary characteristic distribution （GBCD） and the brittle cracking of ferritic stainless steel, the GBCD, impact test and bend test were investigated using scanning electron microscopy （SEM） and the electron backscatter diffraction （EBSD） technique. The results show that a crack occurs preferentially at high angle boundaries, and that low angle and low-∑ coincidence site lattice（CSL） boundaries can offer resistance to the propagation of cracks. It is suggested that an optimum GBCD, i.e. a high frequency of low angle or low-∑ CSL boundaries and discontinuous high angle boundaries network can offer the potential for decreasing the ductile-to-brittle transition temoerature （DBTT） of ferritic stainless steels.展开更多
The feasibility of applying the grain boundary character distribution(GBCD)optimization to Inconel 625 for improving the intergranular corrosion(IGC)resistance was studied.The GBCD was obtained and characterized by el...The feasibility of applying the grain boundary character distribution(GBCD)optimization to Inconel 625 for improving the intergranular corrosion(IGC)resistance was studied.The GBCD was obtained and characterized by electron backscatter diffraction(EBSD)analysis,and its optimization was mainly attributed to annealing twins(Σ3)and twins related to boundaries formed during thermal-mechanical processing(TMP).Through TMP of 5%cold rolling and subsequent annealing at 1150℃for 5 min,the proportion of lowΣcoincidence site lattice(CSL)grain boundaries of the Inconel 625 can be enhanced to about 35.8%which mainly were ofΣ3^(n)(n=1,2,3)type.There is an increase of 24.8%compared with the solution-treated sample,and simultaneously the large-size highly-twinned grain-cluster microstructure is formed.The grain-cluster is mainly composed ofΣ3-Σ3-Σ9 orΣ3-Σ9-Σ27 triple junctions,which is mainly caused by boundary reactions during grain growth.Among them,the IGC resistance ofΣ3 grain boundaries,Σ9 grain boundaries and random grain boundaries is sequentially weakened.With the increase of the lowΣCSL grain boundary fraction,the IGC resistance of Inconel 625 improves.The essential reason is the amount ofΣ3 boundaries interrupting the random boundary network increases and the large grain-cluster arrests the penetration of IGC.展开更多
The recrystallization behavior,grain boundary characteristic distribution,and mechanical properties of pure Cu sheets that were subjected to different cold rolling paths,and then annealed at 400°C for 10,30,60,an...The recrystallization behavior,grain boundary characteristic distribution,and mechanical properties of pure Cu sheets that were subjected to different cold rolling paths,and then annealed at 400°C for 10,30,60,and 420 min,were investigated.Different rolling paths changed the grain boundary orientations of cold-rolled copper,causing recrystallized grains to nucleate and grow in an oriented manner.However,the evolution of the texture indicated that cold-rolled copper with different rolling paths did not show an obvious preferred orientation after annealing.The RD-60 specimen exhibited the smallest grain size(6.6μm).The results indicated that the grain size and low-ΣCSL grain boundaries worked together to provide RD-60 samples with appropriate mechanical properties and high plasticity.The yield strength,ultimate tensile strength,and elongation of RD-60 sample were 81 MPa,230 MPa,and 49%,respectively.These results could provide guidance for tuning the microstructures and properties of pure Cu foils,as well as designing fabrication routes for pure Cu foils through processes such as rolling and drawing.展开更多
文摘In order to better understand the relation between grain boundary characteristic distribution （GBCD） and the brittle cracking of ferritic stainless steel, the GBCD, impact test and bend test were investigated using scanning electron microscopy （SEM） and the electron backscatter diffraction （EBSD） technique. The results show that a crack occurs preferentially at high angle boundaries, and that low angle and low-∑ coincidence site lattice（CSL） boundaries can offer resistance to the propagation of cracks. It is suggested that an optimum GBCD, i.e. a high frequency of low angle or low-∑ CSL boundaries and discontinuous high angle boundaries network can offer the potential for decreasing the ductile-to-brittle transition temoerature （DBTT） of ferritic stainless steels.
基金Funded in part by the National Key Research and Development Program of China(No.2017YFA07007003)the National Natural Science Foundation of China(No.51661019)+1 种基金the Major Projects of Science and Technology in Gansu Province(No.145RTSA004)the Hongliu First-class Discipline Construction Plan of Lanzhou University of Technology。
文摘The feasibility of applying the grain boundary character distribution(GBCD)optimization to Inconel 625 for improving the intergranular corrosion(IGC)resistance was studied.The GBCD was obtained and characterized by electron backscatter diffraction(EBSD)analysis,and its optimization was mainly attributed to annealing twins(Σ3)and twins related to boundaries formed during thermal-mechanical processing(TMP).Through TMP of 5%cold rolling and subsequent annealing at 1150℃for 5 min,the proportion of lowΣcoincidence site lattice(CSL)grain boundaries of the Inconel 625 can be enhanced to about 35.8%which mainly were ofΣ3^(n)(n=1,2,3)type.There is an increase of 24.8%compared with the solution-treated sample,and simultaneously the large-size highly-twinned grain-cluster microstructure is formed.The grain-cluster is mainly composed ofΣ3-Σ3-Σ9 orΣ3-Σ9-Σ27 triple junctions,which is mainly caused by boundary reactions during grain growth.Among them,the IGC resistance ofΣ3 grain boundaries,Σ9 grain boundaries and random grain boundaries is sequentially weakened.With the increase of the lowΣCSL grain boundary fraction,the IGC resistance of Inconel 625 improves.The essential reason is the amount ofΣ3 boundaries interrupting the random boundary network increases and the large grain-cluster arrests the penetration of IGC.
基金financially supported by the National Natural Science Foundation of China(No.52201099)the Scientific Research Starting Foundation of Anhui Polytechnic University,China(No.S022021004)+2 种基金Undergraduate Scientific Research Project of Anhui Polytechnic University,ChinaSchool Level Scientific Research Project of Anhui Polytechnic University,China(No.Xjky2022028)the Open Research Fund of Anhui Key Laboratory of High-Performance Non-ferrous Metal Materials,China(No.YSJS-2023-1)。
文摘The recrystallization behavior,grain boundary characteristic distribution,and mechanical properties of pure Cu sheets that were subjected to different cold rolling paths,and then annealed at 400°C for 10,30,60,and 420 min,were investigated.Different rolling paths changed the grain boundary orientations of cold-rolled copper,causing recrystallized grains to nucleate and grow in an oriented manner.However,the evolution of the texture indicated that cold-rolled copper with different rolling paths did not show an obvious preferred orientation after annealing.The RD-60 specimen exhibited the smallest grain size(6.6μm).The results indicated that the grain size and low-ΣCSL grain boundaries worked together to provide RD-60 samples with appropriate mechanical properties and high plasticity.The yield strength,ultimate tensile strength,and elongation of RD-60 sample were 81 MPa,230 MPa,and 49%,respectively.These results could provide guidance for tuning the microstructures and properties of pure Cu foils,as well as designing fabrication routes for pure Cu foils through processes such as rolling and drawing.
