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1.
低碳钢过冷奥氏体形变过程中的组织及取向变化 总被引:3,自引:0,他引:3
利用SEM,TEM及EBSD研究了低碳钢在750℃ ,10s-1应变速率条件下形变过冷奥氏体的组织及取向变化.结果表明,组织演变由二个阶段组成,形变前期是以形变强化相变铁素体转变为主;当应变达到一定时,以铁素体的动态再结晶为主.应变量较小时,形变强化相变铁素体晶粒优先在原奥氏体晶界形核,随应变量的增加,以相界前沿畸变区的反复形核为主,铁素体转变量逐渐提高,同时珠光体等第二组织增多,铁素体晶粒内部位错密度提高.铁素体连续动态再结晶初期亚晶在珠光体与铁素体交界处优先形成.随应变增加频率提高.形变前期<001>织构为相变铁素体在取向上的特征;形变后期<111>织构是动态再结晶铁素体在取向上的特征. 相似文献
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Q235碳素钢超细铁素体组织的退火过程研究 总被引:1,自引:0,他引:1
在热模拟单向压缩条件下研究了Q235碳素钢形变强化相变产生的超细铁素体退火时的组织及取向(差)演变过程及其应变量和先共析铁素体的影响。结果表明,形变强化相变后细晶铁素体内形变储存能有限,加上渗碳体的钉扎,一般不发生明显的静态再结晶过程。当应变量足够大时,形变后在650℃下保温铁素体发生正常长大。先共析铁素体存在时,形变后在650℃退火时,形变长条铁素体发生明显的(亚)晶粒回复式长大。形变改变了未转变奥氏体的分解方式,表现为奥氏体向离异珠光体的加速转变。讨论了低碳钢形变后铁素体难以再结晶的原因。 相似文献
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深冲SPCE与超深冲IF钢r值差异的ODF分析 总被引:2,自引:0,他引:2
用取向分布函数(ODF)方法对造成IF钢板与SPC钢板r值差异的织构因素进行了分析。结果指出,由于铁素体中间隙原子存在状态不同经冷轧后织构不同,进面经退火后退火织物不同,IF钢的退火织构以{111}<110>,{111}<112>织构为主,SPCE钢的退火织构以{001}<110>织构为主。{111}取向晶为闰的r值大于{001}取向晶粒的r值。因而超深冲IF钢有比深冲SPCE钢板高的r值。 相似文献
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Cu对IF钢再结晶动力学的影响 总被引:2,自引:0,他引:2
用透射电镜(TEM)、扫描探针(EPMA)及其EBSD附件等分析手段系统研究了不同Cu含量对IF钢再结晶动力学行为的影响。结果表明弥散析出的富Cu相阻碍含Cu IF钢的再结晶过程。利用EBSD技术,首次观察地IF钢再结晶显微组织中有两类晶粒:其中一类具有对深冲性有利的γ纤维织构,另一类具有分散的显微织构,其主要组分为RD∥〈110〉,ND∥〈332〉。讨论了两类晶粒的形成机制。 相似文献
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原始晶粒尺寸对低碳钢中铁素体动态再结晶的影响 总被引:4,自引:0,他引:4
采用Gleeble1500型热模拟试验机进行单轴热压缩实验,研究了4种不同原始晶粒尺寸的低碳钢在变形温度为700和600℃,应变速率为10^1-10^-3s^-1条件下的变形特性及组织演变规律,探讨了原始晶粒尺寸和热加工参数Z值对铁素体动态再结晶过程的影响.结果表明:在本实验变形条件范围内,4种不同原始晶粒尺寸的低碳钢均可发生铁素体动态再结晶,原始晶粒尺寸的减小,不但在恒定Z值条件下有利于动态再结晶过程的进行,而且使铁素体可以发生动态再结晶的临界Z值和发生不连续动态再结晶的临界Z值均增大.形变强化相变生成的细小铁素体晶粒在热变形时易于发生动态再结晶,只要控制好热加工参数,可以利用动态再结晶过程,进一步细化形变强化相变生成的铁素体晶粒。 相似文献
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Q235碳素钢应变强化相变的基本特点及影响因素 总被引:35,自引:0,他引:35
在热模拟单向压缩实验中,通过形变参数的变化考察了Q235碳素钢应变强化相变的基本规律及铁素体晶粒细化效果,结果表明,铁素体的超细化在热力学上是由于应变强化相变最大限度地提高了相变过冷度,在动力学上是由于形核集中在局部的高应变区,同时在转变过程中形变不断产生新的形核地点并抑制铁素体生长的结果,实现铁素体的超细化需要一最小变量及一定的应变速率,以使转变完毕并加抑制铁素伯的生长及形变成长条状,应变明显削弱了奥氏体晶粒尺寸的差异带来的铁素体尺寸的差异,应变造成的铁素体动态再结晶进一步细化了晶粒,这种特征是动态转变所特有的,此外,还比较了应变强化相变与无应变及传统近轧控冷铁素体形成时的差异。 相似文献
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超塑Al-Mg-Li合金的显微组织与织构特性 总被引:1,自引:0,他引:1
采用一种新型形变热处理方法制备细晶Al-Mg-Li合金板材,研究静态再结晶退火对合金板材晶粒组织及超塑变形行为的影响。结果表明,晶粒尺寸、形状和织构的分布沿板材法向方向存在明显不同;表面层的晶粒组织细小、等轴,含有旋转cubeND{001}(310)取向;中心层具有粗大、长条状晶粒,含有a取向线的织构组分。随着再结晶温度的升高,整个板材的晶粒尺寸长大,中心层晶粒纵横比减小,表面层织构强化而中心层织构弱化,超塑性伸长率下降。升高再结晶温度导致整个板材内的旋转cubeND{001}(310)织构组分强化而a取向线的织构弱化。分析了不同温度下再结晶织构的形成机制。 相似文献
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采用热模拟方法及EBSD技术,研究Fe-3 wt%Si电工钢在不同温度下组织的动、静态再结晶及晶粒取向特征,特别是少量奥氏体对铁素体动、静态再结晶组织及取向的影响.结果表明,不同温度形变的组织主要分三类:形变长条铁素体、珠光体和等轴细小铁素体.长条形变铁素体内发生动态回复或连续式的动态再结晶,奥氏体周同的铁素体动态再结晶加速,部分以传统的不连续方式动态再结晶.铁素体、奥氏体都可发生静态再结晶.奥氏体的静态再结晶在1050℃以上明显,铁素体的静态再结晶随温度的升高逐渐进行,最显著的再结晶发生在1050℃.不同温度形变的样品,其形变晶粒取向主要以<111>和<100>为主,小等轴铁素体晶粒除与大形变铁素体取向相近外,出现了<110>取向及其它取向. 相似文献
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《金属学报(英文版)》2016,(6)
The significant occupancy of {411}148texture exists in the thin-gauge grain-oriented silicon steel(TGCRGO is defined that thickness of the sheet is0.25 mm and the reduction in cold rolling is more than 90%) which has been considered to have obviously effects on the abnormal growth of Goss-oriented grains during the secondary recrystallization process. The microstructures of the TG-CRGO were investigated by X-ray diffraction and electron back-scattered diffraction in this study. It was found that {411}148texture mainly exists in the center layer of hot-rolled as well as normalized plates.With the increase in cold rolling reduction, {411}148 orientation gradually rotates to a-fiber texture(110//RD).Finally, few {411}148would retain at the boundaries of deformed a-fiber grains(110//RD) as the reduction in cold rolling reaches 90%. After annealing treatment, a small amount of c-fiber textures(111//ND) preferably nucleates and recrystallizes between the DBs(deformation bands) at first; then, the {411}148 recrystallization texture occurs and mainly nucleates at the grains boundaries of the deformed a-fiber grains, and also quite a few {411}148orientation grains nucleate in the inner of {112}110grains. But this phenomenon was not observed in the {100}011deformation grains.With respect to the occurrence of {411}148recrystallization texture, it is mainly induced by strong a-fiber as well as weak c-fiber textures formed during cold rolling other than originating from {411}148 regions in hot bands. 相似文献
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Zhaodong Wang Yanhui Guo Xianghua Liu Guodong Wang Peng Zhang 《Journal of Materials Engineering and Performance》2006,15(6):646-650
The recrystallization textures and drawability in an interstitial-free (IF) steel were investigated as a function of cold
rolling reduction. The hot bands for further cold rolling were obtained by lubricated hot rolling in the ferrite region. The
orientation distribution function (ODF) was applied to analyze recrystallization textures. Texture analysis showed that hot
bands rolled in the ferrite region had strong {111}//ND texture component. The {111}//ND recrystallization texture of the
cold rolled steel with 73% reduction displayed the highest intensity, but weakened as more cold work was introduced. The highestr-value was obtained at a cold reduction of 73% when the hot band was previously rolled in the ferrite region. 相似文献
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Ti-IF钢罩式退火过程中再结晶织构演变规律研究 总被引:1,自引:1,他引:0
采用X射线衍射技术(XRD)和电子背散射衍射技术(EBSD),并结合微观组织观察分析了Ti-IF钢罩式退火过程中织构演变规律和{111}再结晶织构形成机制.结果表明:随退火温度的升高,再结晶量逐渐增多,{111}再结晶织构强度亦逐渐增强,同时{100}织构强度逐渐减弱.{111}取向的品粒主要在再结晶过程中形成,依靠吞并其他取向[主要是{100}取向]的晶粒而长大;并且在{111}取向品粒长大过程中,γ纤维织构之间也发生相互转化,主要由{111}<112>织构转变为{111}<110>织构;冷轧IF钢再结晶退火后具有较强的γ纤维织构,主要是"取向形核"和"取向长大"共同作用的结果,其中Σ重位晶界在再结晶γ纤维织构形成过程中起着重要作用. 相似文献
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Microstructure and texture in 6016 aluminum alloy during hot compression were researched with a uni- axial compression experiment. Through the electron back- scattered diffraction (EBSD) and X-ray diffraction (XRD) analysis technology, it is shown that the subgrain nucle- ation and recrystallization occur in 6016 aluminum alloy during hot compressing, and strong rolling textures such as (110) fiber texture, Brass, S, and Goss form. With the deformation passes increasing, (110) fiber texture, Brass and S are enhanced. In the heat preservation stage after deformation, recrystallization continues until heat preser- vation for 60 s, and a duplex microstructure of deformation and recrystallization grains is built. At the beginning of heat preservation, recrystallization grains with the Goss texture and random orientation are formed in original grains with S or Brass texture, which makes the volume fraction of S and Brass texture decrease. Then, the complex grain growth process makes the volume fraction of Brass, S, and Goss texture increase, while that of random orien- tation decrease. 相似文献
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Influence of initial textures on dynamic recrystallization and textures in AZ31 magnesium alloys 总被引:1,自引:0,他引:1
1 INTRODUCTIONMagnesiumisthelightestmetallicstructurema terialwithhighspecificstrengthandthereforeiswidelyusedinautomotive ,electronicsandaerospaceindustries[1,2 ] .However ,magnesiumoftenshowsinsufficientplasticityatroomtemperatureduetoitsHCPstructurewithlessindependentsystemsofbasalslip .Toenhanceformabilityofmagnesium ,ahigherdeformingtemperatureisusuallyusedwithtwopur poses .Thefirstistoactivatenewslipsystemsbesidesbasalslip ,sothatmorethanfiveindependentslipsystemscanbeprovided ,be… 相似文献
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The significant occupancy of {411}<148> texture exists in the thin-gauge grain-oriented silicon steel (TG-CRGO is defined that thickness of the sheet is <0.25 mm and the reduction in cold rolling is more than 90%) which has been considered to have obviously effects on the abnormal growth of Goss-oriented grains during the secondary recrystallization process. The microstructures of the TG-CRGO were investigated by X-ray diffraction and electron back-scattered diffraction in this study. It was found that {411}<148> texture mainly exists in the center layer of hot-rolled as well as normalized plates. With the increase in cold rolling reduction, {411}<148> orientation gradually rotates to α-fiber texture (<110>//RD). Finally, few {411}<148> would retain at the boundaries of deformed α-fiber grains (<110>//RD) as the reduction in cold rolling reaches 90%. After annealing treatment, a small amount of γ-fiber textures (<111>//ND) preferably nucleates and recrystallizes between the DBs (deformation bands) at first; then, the {411}<148> recrystallization texture occurs and mainly nucleates at the grains boundaries of the deformed α-fiber grains, and also quite a few {411}<148> orientation grains nucleate in the inner of {112}<110> grains. But this phenomenon was not observed in the {100}<011> deformation grains. With respect to the occurrence of {411}<148> recrystallization texture, it is mainly induced by strong α-fiber as well as weak γ-fiber textures formed during cold rolling other than originating from {411}<148> regions in hot bands. 相似文献
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Dong Nyung Lee Hyo- Tae Jeong Hyung- Joon Shin 《Metals and Materials International》1998,4(3):391-396
The recrystallization texture of axisymmetrically deformed fcc metals having major <111> + minor <100> fibers and major <100> + minor <111> fibers is the <100> orientation. The evolution of the 100<001> recrystallization texture from the 112<111> deformation texture and near 031<20 1 3> recrystallization texture from plane strain compressed bicrystal 123<412> and the recrystallization texture of axisymmetrically deformed fcc metals have been discussed based on the energy release maximization theory in which the absolute maximum stress direction in deformed state becomes parallel to the minimum Young’s modulus direction after recrystallization. 相似文献
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W. Mao 《Journal of Materials Engineering and Performance》1999,8(5):556-560
An investigation on recrystallization textures in high purity face-centered cubic (fcc) aluminum, copper, and nickel indicated
that the cube texture is a unique dominant final texture. In a macroview of rolling deformation, a balanced activation of
four slip systems can result in certain stability of some substructure with cube orientation in the deformed matrix. In the
stable substructure the dislocation density is very low, and the dislocation configuration is rather simple in comparison
to other orientations so that the cube substructure can easily be transformed into cube recrystallization nuclei by a recovery
process. A high orientation gradient and correspondingly high angle boundaries to the deformed matrix are usually expected
around the cube nuclei, which, therefore, grow rapidly. After the primary recrystallization, the size of cube grains is much
larger than the grains with other orientations, which will be expensed as the cube grains grow further, so that the cube texture
can finally become a dominant texture component. 相似文献