Effects of High Magnetic Field on Recrystallization Behavior in Fe-Si Alloys

Effects of high magnetic field on recrystallization, coarsening after primary recrystallization and texture evolution were studied in non-oriented and oriented 3% silicon steels. The highest applied magnetic field strength was 10 Tesla. It was found that primary recrystallization process and coarsening after primary recrystallization are both retarded by the application of magnetic field during annealing. A difference between primary recrystallization textures annealed with or without a magnetic field was found in both non-oriented and oriented 3% silicon specimens. It was found that the amount of texture component { 111 }<112> increases by the application of magnetic field during annealing.     

残余碳对取向硅钢初次和二次再结晶的影响

研究了脱碳退火样品中的残余碳对取向硅钢初次和二次再结晶的组织和磁性能的影响。结果表明：随着脱碳退火样品中残余碳含量的提高,初次再结晶的平均晶粒尺寸减小,表层和中心层的晶粒尺寸差增大;初次再结晶的强{111}<110>或{111}<112>织构向强{112}<110>织构转变,部分1/4层的Goss晶粒或{111}<112>晶粒转变为其他取向的晶粒;残余碳含量超过0.0200%后,高温退火样品二次再结晶不完善,磁性能较差。相变是导致上述现象的主要原因。     

退火张力对无取向硅钢再结晶织构和磁性能的影响

采用取向分布函数(ODF)分析了无取向电工钢冷轧板施加不同张力时再结晶退火后组织织构的变化.结果表明,随着退火张力的增加,再结晶晶粒尺寸逐渐增大,当退火张力为4 MPa时,晶粒平均直径达最大值75 μm,且尺寸均匀,Cross织构和立方织构组分也增强,其铁损P1.5/50降低到4.34 W· kg-1,同时磁感Bs.升至1.684 T;当张力增加到6 MPa时,晶粒直径减小至40 μm,{110}<001>和{001}<100>织构组分减弱,γ线织构组分明显增强,磁性能恶化.     

Texture Evolutions in Fe-6.5% Si Produced by Rapid Solidification and Chemical Vapor Deposition

Fe-Si ribbons and thin sheets with 6.5%Si content were prepared by means of the single roller rapid solidification and chemical vapor deposition (CVD), respectively. The initial textures of rapidly solidified Fe-6.5%Si ribbons were characteristic of the {100} fiber-type, which became weakened during primary recrystallization in various atmospheres. At the stage of secondary recrystallization, the {100} texture formed in Ar and the {110} texture in hydrogen, while there occurred a texture transformation from the {100} type to the {110} type in vacuum with the increase of annealing temperature. For Fe-6.5%Si sheets prepared by Si deposition in cold-rolled Fe-3%Si matrix sheets, their textures were dominated by the η-fiber (<001>//RD) with the maximum density at the {120}<001> orientations. After homogenization annealing, the η-fiber could evolve into the {130}<001> type or become more concentrated on the {120}<001> orientations, depending on the cold rolling modes of Fe-3%Si matrix sheets.     

Influence of Rolling Reductions on Recrystallization Texture in Commercially Pure Al

The recrystallization texture in commerciallypure Al is investigated after the samples are rolleddifferently and annealed.The samples with low rol-ling reductions could be generally recovered orrecrystallized in situ and characterized by the re-tained G{110}<001>component.This recoveryprocess decreases during annealing with the increaseof reduction.The appearance of the B/R{359}.<132>and R{123}<634>components de-pending on the rolling reduction is investigated andthe less developed Cube{100}<001>componentin commercially pure ahninium is also discussed.     

Texture Evaluation of α_2 Phase in Ti-25Al-10Nb-3V-1Mo Alloy Sheet

The texture evaluation of α2 phase in Ti-25Al-10Nb-3V-1Mo sheet during rolling and annealing has been investigated by means of microstructure observation and ODF analysis. From the weak initial {1010} (1210) and {0001}(1210) textures a {1210}(1010) texture and a {0001}(uvtw)fibre texture are formed after cold rolling. The {0001} (1210) texture is also strengthened simultaneously. The activation process of slip systems is discussed concerning formation of the rolling texture. Because of the disappearance of {0001} (nvtw) fibre texture the primary recrystallization process should occur and the {1210}(1010) texture forms during annealing     

IF钢铁素体区热轧和退火过程中织构的演变

研究了一种Ti—IF（Interstitial—free）钢在铁素体区热轧和退火过程中织构的变化．由于轧制过程摩擦的影响,热轧织构和退火织构在厚度方向上都有很大的差异．在钢板的表层,热轧织构的主要组分是{110}（001）,退火后表层的铁素体晶粒没有发生再结晶,该组分转变为（001）（110）;在试样的中心和1／4面,热轧织构组分主要是较弱的（111）／／ND（板法向）织构和部分（110）／／RD且在{001}（110）处最强;退火后中心面上的晶粒发生了完全再结晶,{001}组分转变为（111）／／ND组分使（111）／／ND织构成为唯一织构组分且在{111}（112）处最强．     

Rolling and annealing textures of a SiCw/Al composite

A SiC whisker reinforced pure aluminum composite (SiC_w/Al) was fabricated using a squeeze casting route and cold-rolled to 50% reduction in thickness. Some cold-rolled composites were then annealed at 500 °C for 1 h. The pure aluminum was also cold-rolled and annealed in the above way for comparison purpose. The textures of the cold-rolled and annealed materials were examined using XRD technique. It was found that the dominant texture components in the cold-rolled composites consisted of {112}〈111〉, {100}〈011〉 and {123}〈634〉. They were much weaker than those in the cold-rolled aluminum. When the cold-rolled composites were annealed, the new texture components {211}〈213〉, {013}〈131〉 and {011}〈211〉 occurred and had the similar intensity as the texture components remained from the deformation state. This indicated that the recovery reaction and recrystallization occurred simultaneously when the cold-rolled composite was annealed 1 h at 500 °C. Like the situation of the deformed materials, the annealing texture was also much weaker in the composite than in the aluminum. The weaker deformation and annealing textures in the composites can be attributed to the introduction of the whiskers.     

电场对Al-Mn-Mg合金的微结构和织构形成的影响

利用透射电子显微镜观察(TEM)和X射线衍射技术(ODFs分析),研究了电场对Al-Mn-Mg合金的回复和再结晶组织演变、再结晶织构的形成和发展的影响.结果表明,电场对再结晶的影响其强度有一个门槛值(3～4 kV/cm),低于此值电场对该合金的再结晶没有明显的影响.强度为4 kV/cm的电场对再结晶形核的影响较大,可抑制Al-Mn-Mg合金的回复和再结晶,促进再结晶立方织构的形成.其主要原因是电场降低了各取向的形变储能,推迟了再结晶进程,抑制储存能小的取向晶核的形成和长大,促进储存能大的S取向晶粒向立方织构择优生长.     

Effects of external electric field on recrystallization texture and microstructure of 08Al killed steel sheet

The effects of electric field annealing on recovery and recrystallization in a cold-rolled 08Al killed steel sheet were investigated. Results show that, with the application of a DC electric field, the recovery and recrystallization processes are retarded and the recrystallization -fiber texture is strengthened. Those retardation effects are attributed to a decrease of the driving force for recrystallization caused by electric field, which would hinder grain nucleation and growth on the whole. Possible reason for the intensification of the recrystallization -fiber texture through electrical annealing is briefly discussed.     

深冲IF钢再结晶{111}纤维织构形成机制探讨

为了探讨深冲IF钢再结晶织构与退火温度之间的关系及{111}再结晶织构形成机制,采用X射线衍射三维取向(ODF)和背散射电子衍射(EBSD)分析技术并结合金相组织观察,利用Gibbs-Thom son方程对冷轧IF钢在不同退火温度下的再结晶织构演变规律及形成机制进行研究.实验结果表明:随着退火温度的增加,再结晶量逐渐增多,γ纤维织构强度亦相应增强,同时,α纤维织构强度则逐渐降低;冷轧IF钢再结晶初期的织构转变主要发生在γ纤维织构之间.研究表明,再结晶核心的形成主要以"显微择优形核"为主,晶核的长大则主要以择优生长为主,而Σ重位点阵晶界在再结晶γ纤维织构形成过程中起着重要作用.     

Grain morphology and texture evolution of TC21 titanium alloy during annealing with different time

A homogeneous equiaxed‐structure TC21 titanium alloy is hot rolled and annealed for different time ranging from 1 h to 6 h. The grain morphology and texture evolution of α and β phases during annealing are mainly investigated using the electron back‐scattered diffraction characterization. In the early annealing stage, the α grain mainly maintains the elongated morphology generated in the rolling. With increasing annealing time, more and more elongated α grains become equiaxed due to enhanced static recrystallization and boundary splitting. Differently, the β grain exhibits a fully equiaxed morphology all the time due to the sufficient static recrystallization, and get a coarsening with increasing annealing time. The α phase exhibits a (0001) basal texture in the early annealing stage, and then forms a TD‐split texture with increasing annealing time. The β phase exhibits the {001}<110> texture at every annealing time. Based on the analysis about the texture of different grain sizes, the effects of recrystallization nucleation and oriented growth on texture evolution are discussed. It suggests that TD‐split texture in α phase is originated from both the recrystallization nucleation and oriented growth. The formation of {001}<110> texture in β phase is mainly originated from the oriented growth.     

冷轧原料组织对再结晶组织及织构演变影响的研究

取相同的CsP热轧板1#和2#试样,1#试样经热处理将晶粒尺寸调大,2#试样不作组织调整,并进行5道次连轧和罩式退火处理。然后采用基于扫描电镜上电子背散射衍射分析方法研究了冷轧原料组织对再结晶过程中组织和织构演变规律。结果表明：经组织调整后大晶粒的1#试样,作为冷轧原料轧制成的冷轧板后在530℃时就开始发生再结晶,且再结晶晶粒长大比较均匀,而不作组织调整的2#试样经冷轧后在545℃时才有很少量的再结晶晶粒在晶界生成;1#试样在再结晶初期545℃时有利于深冲性能的（111）面织构含量最高且为59．6％,2#试样在575℃时（111）面织构含量最高且为64．1％;根据织构演变规律,1#和2#试样应采用不同分段分级退火工艺,才可使最终冷轧板具有更多的有利于深冲性能的（111）面织和少量的（001）面织构。     

Influence of Widening on the Rolling and Recrystallization Texture in High Purity Al with Initial Cube Texture

The influence of widening and initial Cube tex-ture on formation of rolling and recrystallizationtexture was investigated in high purity Al.With in-creasing widening the initial Cube texture has ro-tated more around rolling direction(RD)and lessaround transverse direction(TD).Therefore,moreorientations rotate in x-fibre between G{110}<001>and B{110}<112>positions,and less inS{124}<211>texture component,which showsthe widening plays an important role in the forma-tion of S component during rolling.The relation-ship between rolling and recrystallization texturecomponents is discussed.Though the transitionband predicted by Dillamore and Katoh is alwaysformed during rolling,the most important factor in-fluencing recrystallization texture should be the ori-ented growth according to the changes of volumefractions and scatter widths of texture componentswith widening.     

Texture mechanism in some fcc-type soft magnetic materials

The authors have studied the mechanism for recrystallization texture in some soft magnetic materials with fcc crystal structure. The alloys used were 77% Ni-14% Fe-5% Cu-4 wt% Mo permalloys. Thin foils selected area electron diffraction (SAD) and X-ray diffraction techniques were employed using a Philips 300 Electron Microscope (EM 300) and an X-ray diffractometer, respectively. Investigations were carried out on deformed, recovered and recrystallized states of the alloys. The various results show that the cold-rolled (deformed) and recovered states of the alloys possess copper-type of rolling texture with {110} 〈112〉 texture as the predominant deformation texture though other minor components such as {112} 〈111〉, {110} 〈001〉 and {123} 〈420〉 textures were detected. No cube texture, {100} 〈001〉 was detected in any of the deformed and recovered materials though the recrystallization texture in these alloys is the cube texture, {100} 〈001〉 which forms over 80% of the annealing texture in these alloys. It is concluded here that the detection of cube texture in the deformed and recovered materials is not a prerequisite for the detection of cube texture in these alloys. The present work is not conclusive about the mechanism for recrystallization texture, but it is proposed here that recrystallization texture, in these alloys is attributed to the growth-oriented mechanism based on the following model. (1) The lattice domains which form the recrystallization texture are present in the cold-rolled matrix. (2) The favoured site for nucleation are the grain boundaries and deformation band boundaries. (3) For the nucleus to be able to grow and form the recrystallization texture it must possess the necessary free energy. (4) Grains must be capable of growth into two or more orientations between which it forms, i.e. the nuclei which form the cube texture should have a [111] pole in common with the matrix in which they grow and a rotation of about 30° around this pole.     

Microstructural evolution of annealed Al–5 wt% Ca–5 wt% Zn sheet alloy

Microstructural evolution on annealing of Al–5 wt% Ca–5 wt% Zn sheet alloy has been systematically investigated by means of texture analysis and optical and transmission electron microscopy. Heat treatments in the temperature range of 100 to 540 °C for times between 0.11 (7 min) and 90.5 h have been performed. After annealing, the main texture component of the as- received material, {1 1 3} <3 3 2>, was retained, whereas the minor components, {0 1 3} <3 1 0> and {0 1 1} <1 0 0>, showed clear changes depending on the annealing conditions. Additional minor components appeared upon heat treatments. Continuous recrystallization, subgrain accommodation by means of rotation and subsequent extensive grain growth are the processes which account for all the microstructural changes observed. This revised version was published online in November 2006 with corrections to the Cover Date.     

高强Ti-IF钢铁素体区热轧和冷轧过程织构演变规律

为了揭示铁素体区热轧、冷轧和退火过程中高强Ti-IF钢中织构的演变过程,采用X射线衍射仪研究了铁素体区热轧及随后的冷轧和退火织构的特点.研究表明,在铁素体区热轧后,表面和中心面的织构类型和强度不尽相同,表面上的主要织构组分是剪切织构{110}<001>,而中心面上的主要织构组分是{001}<110>～{223}<110>和{111}<110>,由于织构的遗传性,冷轧和退火后的织构在表面和中心面上也不相同;经不同压下率冷轧后,织构变化趋势一致,表面上{110}<001>组分消失,{001}<110>成为最强组分,而中心面上最强组分由{001}<110>沿α取向线向{112}<110>偏移,冷轧织构由α织构和γ织构组成;退火后,表面上织构的变化与以往结论有所不同,{001}<110>～{112}<110>组分减弱,而γ取向线上的{111}<123>组分增强,{111}<112>和{111}<110>减弱.     

Investigation of structure and texture development during annealing of low-carbon steel

Abstract

The effect of carbon in different states of dispersion has been examined in relation to its effect on the texture formed during the annealing of cold-rolled steel sheet. Quantitative texture analyses using orientation distribution functions have been combined with detailed metallographic investigation of changes taking place during recrystallization. Calculations have also been carried out on the rate of dissolution of carbon from cementite particles for a range of relevant conditions. Dissolved carbon present before cold rolling greatly reduces the final annealed {111} texture strength and leads instead to a spread around the Goss orientation. Dissolved carbon present with manganese during annealing also reduces the final {111} intensity, tending to replace it with a number of relatively weak minor components; this is observed during conditions of slow heating, or when primary carbide particles are numerous, and seems to be associated with a significant nucleation rate of new grains during the later stages of recrystallization.

MST/389     

Electron backscatter diffraction study of deformation and recrystallization textures of individual phases in a cross-rolled duplex steel

The evolution of microstructure and texture during cross-rolling and annealing was investigated by electron backscatter diffraction in a ferritic–austenitic duplex stainless steel. For this purpose an alloy with nearly equal volume fraction of the two phases was deformed by multi-pass cross-rolling process up to 90% reduction in thickness. The rolling and transverse directions were mutually interchanged in each pass by rotating the sample by 90° around the normal direction. In order to avoid deformation induced phase transformation and dynamic strain aging, the rolling was carried out at an optimized temperature of 898 K (625 °C) at the warm-deformation range. The microstructure after cross warm-rolling revealed a lamellar structure with alternate arrangement of the bands of two phases. Strong brass and rotated brass components were observed in austenite in the steel after processing by cross warm-rolling. The ferrite in the cross warm-rolling processed steel showed remarkably strong RD-fiber (RD//< 011 >) component {001}< 011 >. The development of texture in the two phases after processing by cross warm-rolling could be explained by the stability of the texture components. During isothermal annealing of the 90% cross warm-rolling processed material the lamellar morphology was retained before collapse of the lamellar structure to the mutual interpenetration of the phase bands. Ferrite showed recovery resulting in annealing texture similar to the deformation texture. In contrast, the austenite showed primary recrystallization without preferential orientation selection leading to the retention of deformation texture. The evolution of deformation and annealing texture in the two phases of the steel was independent of one another.     

Texture and microstructure changes in asymmetrically hot rolled AZ31 magnesium alloy sheets

Asymmetrically hot rolled AZ31 magnesium alloy sheets exhibited a texture gradient, where the intensity of {0002} basal textures decreased from the upper surface through the center to the lower surface. After subsequent annealing, the intensity of {0002} components was reduced significantly throughout the thickness and the grains were refined possibly by discontinuous recrystallization.