Based on the relationship between parameters of grain boundary internal friction peak(GBP)andgrain boundary character distribution(GBCD),and the internal friction results of Al-Mg,Al-Ga,Al-Cu andAl-Zn alloys,the addit...Based on the relationship between parameters of grain boundary internal friction peak(GBP)andgrain boundary character distribution(GBCD),and the internal friction results of Al-Mg,Al-Ga,Al-Cu andAl-Zn alloys,the addition of different kinds of solute atoms has different effects on GBCD.Among them,Mg atoms are able to concentrate and stabilize GBCD in AI-Mg alloys.The origin of these effects of soluteatoms on GBCD is also discussed.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
18 Mn18 Cr0.5 N steel with an initial grain size of 28–177 μm was processed by 2.5%–20% cold rolling and annealing at 1000°C for 24 h,and the grain boundary character distribution was examined via electron bac...18 Mn18 Cr0.5 N steel with an initial grain size of 28–177 μm was processed by 2.5%–20% cold rolling and annealing at 1000°C for 24 h,and the grain boundary character distribution was examined via electron backscatter diffraction.Low strain(2.5%) favored the formation of low-Σ boundaries.At this strain,the fraction of low-Σ boundaries was insensitive to the initial grain size.However,specimens with fine initial grains showed decreasing grain size after grain boundary engineering processing.The fraction of low-Σ boundaries and the(Σ9 + Σ27)/Σ3 value decreased with increasing strain; furthermore,the specimens with fine initial grain size were sensitive to the strain.Finally,the effects of the initial grain size and strain on the grain boundary engineering were discussed in detail.展开更多
High-strength interstitial-free steel sheets have very good deep drawability when processed to have{111}recrystallization texture.The microtexture evolution and grain boundary character distribution of interstitial-fr...High-strength interstitial-free steel sheets have very good deep drawability when processed to have{111}recrystallization texture.The microtexture evolution and grain boundary character distribution of interstitial-free steels as a function of moderate levels of cold rolling reductions were investigated by the metallographic microscopy and electron backscatter diffraction technique.The results showed that there was a close relationship between microtexture and grain boundary character distribution for interstitial-free steel,especially the distribution and features of some specific types of coincident-site lattice boundaries.In addition,α-fiber texture was weakened to vanish whileγ-fiber texture strengthened gradually as cold rolling reduction was increased from 20%to 75%for cold rolled and annealed samples.Accordingly,increasing the rolling reduction from 20%to 75%would lead to a significant increase in the proportion ofΣ3boundaries.Also,it was found that the microtexture of 20%cold rolled sample would induce a high frequency ofΣ11grain boundaries,but the microtexture of 75%cold rolled sample would produce moreΣ7andΣ17grain boundaries.It was suggested that texture played a significant role in the formation of grain boundary character distribution.展开更多
The grain boundary character distribution(GBCD) optimization and its effect on the intergranular stress corrosion cracking(IGSCC) resistance in a cold-rolled and subsequently annealed Fe-18 Cr-17 Mn-2 Mo-0.85 N high-n...The grain boundary character distribution(GBCD) optimization and its effect on the intergranular stress corrosion cracking(IGSCC) resistance in a cold-rolled and subsequently annealed Fe-18 Cr-17 Mn-2 Mo-0.85 N high-nitrogen nickel-free austenitic stainless steel were systematically explored.The results show that stacking faults and planar slip bands appearing at the right amount of deformation(lower than 10%) are beneficial cold-rolled microstructures to the GBCD optimization.The proportion of special boundaries gradually increases in the subsequent stages of recrystallization and grain growth,accompanying with the growth of twin-related domain in the experimental steel.In this way,the fraction of low ∑ coincidence site lattice(CSL) boundaries can reach as high as 82.85% for the specimen cold-rolled by 5% and then annealed at 1423 K for 72 h.After GBCD optimization,low ∑ CSL boundaries and the special triple junctions(J2,J3) of high proportion can greatly hinder the nitride precipitation along grain boundaries and enhance the capability for intergranular crack arrest,thus improving the IGSCC resistance of the experimental steel.展开更多
研究晶界工程处理过程中的冷轧变形量和再结晶退火对白铜B10合金晶界特征分布的影响,采用电子背散射衍射(EBSD)技术表征分析晶界网络的变化。结果表明:白铜B10合金经冷轧7%后在800℃退火10 min可使低ΣCSL(Coincidence site lattice,Σ...研究晶界工程处理过程中的冷轧变形量和再结晶退火对白铜B10合金晶界特征分布的影响,采用电子背散射衍射(EBSD)技术表征分析晶界网络的变化。结果表明:白铜B10合金经冷轧7%后在800℃退火10 min可使低ΣCSL(Coincidence site lattice,Σ≤29)晶界比例提高到75%以上,同时形成尺寸较大的"互有Σ3n取向关系晶粒的团簇"显微组织。当变形量小于7%时,经800℃退火后没有完全再结晶;当变形量大于7%时,低ΣCSL晶界比例和平均晶粒团簇的尺寸随冷轧变形量的增加而下降。展开更多
应用电子背散射衍射(EBSD)和取向成像显微技术(OIM)研究了材料初始状态、冷轧压下量和1100℃退火对690合金晶界特征分布(GBCD)的影响。低层错能面心立方金属镍基690合金,冷轧5%后在1100℃退火5min可使低ΣCSL(coincidence site lattice...应用电子背散射衍射(EBSD)和取向成像显微技术(OIM)研究了材料初始状态、冷轧压下量和1100℃退火对690合金晶界特征分布(GBCD)的影响。低层错能面心立方金属镍基690合金,冷轧5%后在1100℃退火5min可使低ΣCSL(coincidence site lattice,Σ≤29)晶界比例提高到70%以上(Palumbo-Aust标准),同时形成大尺寸的晶粒团簇。低ΣCSL晶界比例和这种晶粒团簇的尺寸随冷轧压下量的增加而下降。初始状态的固溶或时效对690合金在1100℃再结晶退火后的晶界特征分布无明显影响。展开更多
文摘Based on the relationship between parameters of grain boundary internal friction peak(GBP)andgrain boundary character distribution(GBCD),and the internal friction results of Al-Mg,Al-Ga,Al-Cu andAl-Zn alloys,the addition of different kinds of solute atoms has different effects on GBCD.Among them,Mg atoms are able to concentrate and stabilize GBCD in AI-Mg alloys.The origin of these effects of soluteatoms on GBCD is also discussed.
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.51505416)the Natural Science Foundation-Steel and Iron Foundation of Hebei Province,China (No.E2017203041)+1 种基金the Natural Science Foundation of Hebei Province,China (No.E2016203436)the Post-Doctoral Research Project of Hebei Province,China (No.B2016003029)
文摘18 Mn18 Cr0.5 N steel with an initial grain size of 28–177 μm was processed by 2.5%–20% cold rolling and annealing at 1000°C for 24 h,and the grain boundary character distribution was examined via electron backscatter diffraction.Low strain(2.5%) favored the formation of low-Σ boundaries.At this strain,the fraction of low-Σ boundaries was insensitive to the initial grain size.However,specimens with fine initial grains showed decreasing grain size after grain boundary engineering processing.The fraction of low-Σ boundaries and the(Σ9 + Σ27)/Σ3 value decreased with increasing strain; furthermore,the specimens with fine initial grain size were sensitive to the strain.Finally,the effects of the initial grain size and strain on the grain boundary engineering were discussed in detail.
基金Item Sponsored by National Natural Science Foundation of China(50901054,51101114)
文摘High-strength interstitial-free steel sheets have very good deep drawability when processed to have{111}recrystallization texture.The microtexture evolution and grain boundary character distribution of interstitial-free steels as a function of moderate levels of cold rolling reductions were investigated by the metallographic microscopy and electron backscatter diffraction technique.The results showed that there was a close relationship between microtexture and grain boundary character distribution for interstitial-free steel,especially the distribution and features of some specific types of coincident-site lattice boundaries.In addition,α-fiber texture was weakened to vanish whileγ-fiber texture strengthened gradually as cold rolling reduction was increased from 20%to 75%for cold rolled and annealed samples.Accordingly,increasing the rolling reduction from 20%to 75%would lead to a significant increase in the proportion ofΣ3boundaries.Also,it was found that the microtexture of 20%cold rolled sample would induce a high frequency ofΣ11grain boundaries,but the microtexture of 75%cold rolled sample would produce moreΣ7andΣ17grain boundaries.It was suggested that texture played a significant role in the formation of grain boundary character distribution.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.51871048 and 52171108)the Fundamental Research Funds for the Central Universities(Grant Nos.N2002014 and N2202011)。
文摘The grain boundary character distribution(GBCD) optimization and its effect on the intergranular stress corrosion cracking(IGSCC) resistance in a cold-rolled and subsequently annealed Fe-18 Cr-17 Mn-2 Mo-0.85 N high-nitrogen nickel-free austenitic stainless steel were systematically explored.The results show that stacking faults and planar slip bands appearing at the right amount of deformation(lower than 10%) are beneficial cold-rolled microstructures to the GBCD optimization.The proportion of special boundaries gradually increases in the subsequent stages of recrystallization and grain growth,accompanying with the growth of twin-related domain in the experimental steel.In this way,the fraction of low ∑ coincidence site lattice(CSL) boundaries can reach as high as 82.85% for the specimen cold-rolled by 5% and then annealed at 1423 K for 72 h.After GBCD optimization,low ∑ CSL boundaries and the special triple junctions(J2,J3) of high proportion can greatly hinder the nitride precipitation along grain boundaries and enhance the capability for intergranular crack arrest,thus improving the IGSCC resistance of the experimental steel.
文摘研究晶界工程处理过程中的冷轧变形量和再结晶退火对白铜B10合金晶界特征分布的影响,采用电子背散射衍射(EBSD)技术表征分析晶界网络的变化。结果表明:白铜B10合金经冷轧7%后在800℃退火10 min可使低ΣCSL(Coincidence site lattice,Σ≤29)晶界比例提高到75%以上,同时形成尺寸较大的"互有Σ3n取向关系晶粒的团簇"显微组织。当变形量小于7%时,经800℃退火后没有完全再结晶;当变形量大于7%时,低ΣCSL晶界比例和平均晶粒团簇的尺寸随冷轧变形量的增加而下降。
文摘应用电子背散射衍射(EBSD)和取向成像显微技术(OIM)研究了材料初始状态、冷轧压下量和1100℃退火对690合金晶界特征分布(GBCD)的影响。低层错能面心立方金属镍基690合金,冷轧5%后在1100℃退火5min可使低ΣCSL(coincidence site lattice,Σ≤29)晶界比例提高到70%以上(Palumbo-Aust标准),同时形成大尺寸的晶粒团簇。低ΣCSL晶界比例和这种晶粒团簇的尺寸随冷轧压下量的增加而下降。初始状态的固溶或时效对690合金在1100℃再结晶退火后的晶界特征分布无明显影响。