退火工艺对3.15 % Si冷轧无取向硅钢组织和织构的影响

试验研究了退火温度（850~950℃）和时间（5~18 min）对2.3 mm热轧硅钢板（/%:0.036C,3.15Si,0.21Mn,0.005P,0.007S,0.032Al）6道次轧制的0.35 mm冷轧板组织和织构的影响。结果表明,退火温度越高,晶粒平均尺寸越大,900℃5 min退火时平均晶粒尺寸41.39μm,试样织构主要集中在γ取向线上的{111}＜112＞;织构组分和{111}＜110＞;织构组分;900℃18 min退火时平均晶粒尺寸为48.08μm,试样的{111}面织构和{112}面织构密度都明显减弱,{001}面织构增强,磁性能较优。     

Recrystallization and grain growth in titanium: I. characterization of the structure

Transmission electron microscopy, quantitative optical microscopy, and texture studies were made on swaged and recrystallized titanium wire of three impurity contents: zone refined, a special lot of intermediate purity, and commercial A-70. The electron microscopy studies revealed that a) during recrystallization a number of processes overlap, and b) during grain growth there occurs a decrease in the dislocation density within the grains along with the increase in the average grain size. The quantitative microscopy studies indicated that the linear intercept grain size distribution is approximately log normal and that for a given mean grain size the distribution is relatively independent of the combination of annealing time and temperature used to obtain it. Moreover, there exists a range of grain sizes in space, the numbers of grains in each class interval changing with increase in grain size. The so-called grain shape factor decreases with increase in mean grain size (annealing time) at a constant temperature and with decrease in temperature for a constant grain size. The texture of the as-swaged wire and the changes in the texture during grain growth are in qualitative accord with those previously reported for deformed and recrystallized titanium. Impurity content influences the degree of these various structural characteristics but not their substance. K. Okazaki, Formerly Visiting Research Associate, Metallurgical Engineering and Materials Science Department, University of Kentucky, Lexington, Ky.     

Characterization of recrystallization and grain growth in Ti-7.4 At. Pct Al (cph) and Ti-15.2 At. Pct Mo (bcc) alloys

Quantitative microscopy, texture and grain growth kinetic studies were made on swaged and recrystallized Ti-7.4 at. pct Al and Ti-15.2 at. pct Mo alloys. The quantitative microscopy studies indicated that the grain size distribution in both alloys is a constant for a given grain size, independent of annealing time and temperature and follows a log normal distribution. Moreover, there exists a range of grain sizes in space; the relative quantities of each size in the range varies with average grain size. Also, the grain shape factor decreases with increase in annealing time (grain size) at a constant temperature and with decrease in temperature for a constant grain size. The values of the shape factor for a given grain size and temperature were approximately the same for the two alloys. The quantitative microscopy features were essentially the same as those observed by Okazaki and Conrad for unalloyed titanium. The texture of the as-swaged Ti-7.4 at. pct Al wire specimens and the changes in this texture during grain growth were in accord with those previously reported for deformed and recrystallized titanium. The Ti-15.2 at. pct Mo alloy retained the deformation texture even after recrystallization. At ^1/3 time law was found to hold for the grain growth over most of the grain sizevs time curve. The values of the activation energy for grain boundary migration were 25.2 Kcal/mole for the Ti-7.4 at. pct Al alloy and 29 Kcal/mole for the Ti-15.2 at. pct Mo alloy. These are similar to those for diffusion of Al and Mo in titanium, indicating that the diffusion of these substitutional elements controls the rate of boundary migration in these alloys. This paper is based on a presentation made at a symposium on “Recovery, Recrystallization and Grain Growth in Materials” held at the Chicago meeting of The Metallurgical Society of AIME, October 1977, under the sponsorship of the Physical Metallurgy Committee.     

退火温度对双辊薄带连铸高强度无取向硅钢组织和性能的影响

摘要：研究了退火温度对双辊薄带连铸Si质量分数为3.2%的高强度无取向硅钢组织、织构和性能的影响。结果表明,700℃保温时试验钢开始发生再结晶;800℃保温时,试验钢已完全再结晶,平均晶粒尺寸为26.4μm;900和1000℃保温时,试验钢中的晶粒开始逐渐长大,平均晶粒尺寸分别长大到33.8和40.9μm,且900℃退火时晶粒组织最均匀。随着退火温度的升高,试验钢中有利织构组分λ织构逐渐增强,Goss织构则在900℃退火时强度最强。因此,试验钢在900℃退火时有利于兼顾磁性能和力学性能。     

A Three-Dimensional Cellular Automata Model Coupling Energy and Curvature-Driven Mechanisms for Austenitic Grain Growth

A 3D cellular automata model is used to simulate normal austenitic grain growth in this study. The proposed model considers both the curvature- and thermodynamics-driven mechanisms of growth. The 3D grain growth kinetics shows good agreement with the Beck equation. Moreover, the growth exponent and grain size distribution calculated by the proposed model coincides well with experimental and simulation results from other researchers. A linear relationship is found between the average relative grain size and the grain face number. More specifically, for average relative grain sizes exceeding ~0.5, the number of faces increases linearly with relative grain size. For average relative grain sizes <0.5, this relationship is changed. Results simulated by the proposed model are translated to physical meaning by adjusting the actual temperature, space, and time for austenitic grain growth. The calibrated results are found to be in agreement with the simulation results from other research as well as the experimental results. By means of calibration of the proposed model, we can reliably predict the grain size in actual grain growth.     

纳米粉末溶解法制备粗晶WC-Co硬质合金

特粗晶硬质合金是一类发展中的先进矿业用硬质合金。采用纳米粉末溶解法制备特粗晶硬质合金,得到WC平均晶粒尺寸为8~9μm的特粗WC-Co硬质合金,研究发现纳米粉末可通过扩散机制控制小晶粒粗化。此方法不仅使WC平均晶粒尺寸增加,而且使WC-Co硬质合金的WC晶粒尺寸分布的均匀性得到提高;同时复杂形状晶粒明显减少,晶粒发育得到改善。     

加热速率对Nb-IF钢退火组织及织构特征的影响

以一种冷轧Nb - IF钢为研究对象,研究了不同加热速率下退火板的微观组织和织构特征.结果表明:当加热速率由10℃/s增加到150℃/s时,再结晶晶粒平均直径由16.72 μm细化到13.8 μm;当加热速率高于100℃/s时,平均晶粒直径变化趋于平缓.试验钢完全再结晶晶粒以大角晶界为主,随加热速率变化,其含量在81.3％～86.9％范围内波动,重位点阵(CSL)含量在34.1％～44.5％之间波动.在快速加热退火和普通加热退火条件下,试验钢均可获得强烈的γ织构,强点密度在f(g)=9.01～ 10.42范围内.     

某难选钨多金属矿的工艺矿物学研究

通过详细的化学多元素分析,光片、薄片矿相显微镜镜下鉴定和扫描电镜能谱分析的方法对某难选钨多金属矿石进行系统的工艺矿物学研究,除查明该矿石中的矿物组成,主要金属矿物的产出特征,嵌布关系和浸染粒度,矿石的构造和矿物的结构特点外,重点使用扫描电镜能谱仪分析的手段,查清有价元素的赋存状态和主要矿物的元素组成等工艺矿物学特征,再根据有价元素在各矿物中的配分计算结果,查清有价元素W、Sn、Cu、Zn在各矿物中所占的比例和呈分散状态的比例,预测该矿石中各有价元素的最大回收率、精矿的最高品位、尾矿的合理损失品位和去除有害杂质的可能性,分析出矿石难分难选的几个主要因素等,为确定合理的选矿工艺流程及条件提供重要依据。     

The Effect of Mn-rich Precipitates on the Strength of AZ31 Extrudates

The commercial magnesium alloy AZ31 has been subjected to a range of solution treatment regimes. These have then been extruded and their microstructure, texture, and precipitate populations characterized along with their mechanical properties. During the solution treatment, Mn-enriched particles develop and these remain largely unchanged throughout subsequent processing steps. A direct link between grain size and texture has been found, with coarser-grained specimens showing sharper textures. VPSC modeling has been used to quantify the effect of texture on the tensile yield strength, and it has been found that sharper textures have larger tensile yield strengths. Since coarser grain sizes have reduced Hall–Petch hardening, but have an additional texture-strengthening component, a region on the Hall–Petch plot for tension has been identified in which there is an insensitivity of strength to grain size. This has been quantitatively modeled and a texture-modified Hall–Petch plot for tension has been developed. The Mn-rich particles have also been shown to provide precipitate strengthening to the alloy of up to 40 MPa. The compressive behavior was clearer, with the compressive yield strength being directly correlated to grain size and unaffected by texture or precipitation hardening.     

Evolution of local texture and grain boundary characteristics during secondary recrystallisation of Fe-3% Si sheets

A study of the evolution of the local texture has shown that the migration rate of special boundaries is higher than that of general boundaries in a polycrystalline materials. The results of the evolution of the local texture are consistent with those related to the anisotropy of grain boundaries migration velocity surrounding the growing Goss grain. Furthermore, it has been taken i nto consideration that, on an average, all grains having an orientation relationship corresponding to that of a special boundary with the Goss grain have the same “texture” effect relative to its growth; these grains have been considered as a texture component belonging to orientations present in the sheet. The amount of grains belonging to this component is much more important than that of the Goss component and their mean grain size is higher than that of {110} 〈001〉 grains: results point out that grain boundaries between these two “components” of texture have a very high diffusivity. In these conditions, the growth model developed by Abbruzzese and Lucke predicts a high growth rate of a small amount of Goss grains to the detriment of the other component: this mode of growth corresponds well to the case of secondary recrystallisation.     

Textural and microstructural gradient effects on the mechanical behavior of a tantalum plate

The effects of gradients in the texture and microstructure of a tantalum plate on mechanical behavior are examined. In particular, the effects of variations in grain size and texture from the surface of the plate to the centerline on the yield behavior and final shape of compression samples are investigated. Individual lattice orientations were measured on samples both before and after deformation using automatic analysis of electron backscatter diffraction patterns. These data were used as input to a polycrystal plasticity model based on the Taylor assumption of uniform strain. Results are compared from experimental and simulated compression tests. The effects of the texture and grain size gradients on these results are discussed. The influence of the texture gradient was found to be the dominating factor controlling the nonuniform plastic response of the material. This work also demonstrates the capability of currently available tools for characterizing inhomogeneous microstructures and modeling the effects of variations in texture and microstructure on mechanical behavior.     

基于电子背散射衍射技术的低碳钢原奥氏体晶界的显示技术探讨

常规对原奥氏体晶界的显示均采用晶界腐蚀法,但是该方法成功率不高,具有一定的局限性,且所使用的苦味酸溶液属于危险品,因此,为了更好地显示出原奥氏体晶界,实验借助电子背散射衍射技术(EBSD)对低碳钢原奥氏体晶界的显示方法进行了详细研究。结果表明,与常规的晶界腐蚀法相比,借助EBSD技术可以显示原奥氏体晶界,其最佳晶界取向差在20°~50 °之间,且该低碳钢原奥氏体平均晶粒尺寸为40.02μm,与晶界腐蚀法统计的结果基本一致,但是对于经过大变形的原奥氏体晶界,实验方法并不适用,这可能与变形后马氏体变体之间的取向差随之变化有关。     

稀土Y在电磁搅拌条件下对半固态ZL101铝合金初生α相的影响

选用稀土Y 作为ZL101 铝合金的细化剂,同时结合自制变频控制的电磁搅拌设备对合金进行短时弱电磁搅拌,探讨了稀土细化半固态合金的机制和不同电磁搅拌频率,对半固态ZL101-Y 铝合金凝固组织中不同区域的初生α 相的影响及最佳的电磁搅拌频率参数.研究表明:液态ZL101-Y合金经620 ℃低过热度浇注,并在频率为30 Hz 的条件下搅拌15 s,于590 ℃保温5 min 后,其初生α 相的形貌和尺寸达到最佳,其中心部晶粒平均等积圆直径为64.95 μm,平均形状因子为0.80,而边缘晶粒的平均等积圆直径为58.97 μm,平均形状因子达到0.83.在此条件下,半固态ZL101 合金浆料的初生α 相形貌及尺寸好且沿径向分布较均匀.      

Austenite Grain Coarsening Behaviour in a Medium Carbon Si‐Cr Spring Steel with and without Vanadium

The austenite grain coarsening behaviour in a medium carbon Si‐Cr spring steel with and without vanadium was investigated by the thermal etching method. This method is efficient when the austenitization temperature is not lower than 900 °C. The average grain sizes on the surfaces of the samples determined by thermal etching vary little from those in the bulk as revealed by chemical etching. The austenite grain coarsening behaviour of the steel with vanadium can be classified in three temperature regimes. Below a critical temperature the vanadium addition is effective to impede grain growth and fine grains are observed. The austenite grain size was significantly smaller than in the steel without vanadium. In a medium temperature regime the steel with vanadium exhibits a bimodal grain size distribution. Above the dissolution temperature of vanadium carbides normal grain growth is observed. An equation was set up to predict the grain coarsening behaviour in the steel without vanadium. The results show how the austenite grain size, which is very important for the toughness and ductility of the spring steels, can be controlled by microalloying with vanadium.     

Wavelet Analysis of Soil Mass Images for Particle Size Determination

A method for determination of average grain size from images of fairly uniform particle size soil masses is presented. The procedure utilizes two-dimensional wavelet decomposition of gray scale images. Earlier attempts to quantify grain sizes based on the statistics of co-occurrence matrices suffered from dependence on the illumination intensity and soil color. By normalizing the energy distribution from wavelet decomposition the effects of these previously problematic factors have been eliminated. A general relationship between the center of area beneath the normalized energy distribution and the perceived particle size in pixels per diameter (PPD) is established. A sample problem demonstrates that the proposed wavelet decomposition method provides accurate grain sizes for a wide range of magnification levels as long as the resulting PPD is between approximately 1 and 50.     

热挤压对FGH96镍基粉末高温合金微观组织的影响

研究了热挤压温度、挤压比、挤压速度、挤压前预处理对FGH96镍基粉末高温合金微观组织的影响规律,确定了获得晶粒尺寸小于10 μm的超塑性细晶组织的热挤压方法。研究结果表明,热等静压后FGH96合金发生了再结晶,实现了粉末的完全致密化成形,但晶粒大小极不均匀,且存在明显的原始颗粒边界(PPB)缺陷。采用热挤压前预处理工艺在确保合金晶粒不长大的同时,又可使γ'相粗化,显著降低热挤压变形抗力。随着挤压温度的升高,合金晶粒尺寸呈长大趋势。挤压温度为1 080 ℃时,获得平均晶粒小于10 μm的完全再结晶超塑性组织,挤压温度继续升高,晶粒尺寸将明显长大。随着挤压比的增大,挤压载荷明显增大,采用大于6∶1的挤压比,有利于获得平均晶粒小于10 μm的完全再结晶超塑性组织。载荷随热挤压速度的升高而增大,在保证合金组织为细晶的条件下,应尽量选择较低的挤压速度。由于在热挤压过程中合金已发生了完全的动态再结晶,未观察到明显的取向,力学性能测试结果也表明沿着挤压方向和垂直于挤压方向的性能相当,说明不同挤压方向的微织构对性能没有明显影响。     

Influence of inhibitors on primary recrystallization structure of Hi- B electrical steel

The influence of different inhibitors on textures after primary recrystallization(830??,5min) of Hi- B steel manufactured by stimulating CSP process was studied by Zeiss Axioplan optical microscope(OM), NOVA400 Nano field emission scanning electron microscope (SEM), electron back- scattered diffraction(EBSD), JEM- 2100 transmission electron microscope (TEM) and energy dispersive spectrometry(EDS) which specimen was made by the second extraction replica method. The results show that the average grain size of sample A is smaller than that of sample B. The inhibitors of sample A and B are mainly Cu2S and AlN, MnS and AlN. Contents of favorable Goss and {110}??112?? texture of sample A are relatively more than that of sample B. The contents of unfavorable texture such as {110}??112?? texture are relatively small. More ??3, ??5 and ??9 CSL grain boundaries occur in the sample A.     

铌对低温取向硅钢初次再结晶行为的影响

以含铌取向硅钢铸坯低温加热制备高磁感取向硅钢为研究目标,通过研究铌对低温取向硅钢初次再结晶行为的影响,达到获得有利于二次再结晶发展的初次再结晶组织目的,采用OM和EBSD技术主要对比了 0.055％铌和不含铌对低温取向硅钢中间退火板的初次再结晶组织、织构和晶界特征的影响.结果表明,铌的加入,使硅钢基体中形成了细小弥散的...     

The effect of penultimate grain size on rolling texture in cu-Sn alloys

The effect of penultimate grain size on the texture of Cu-Sn alloys has been investigated using the modulus method. It was observed that in alloys which exhibited the brass-type texture, the large grained specimens yielded a smaller proportion of textured material than those which were fine grained. In alloys which exhibited transition textures, however, the larger grain size specimens exhibited a greater amount of material residing in the brass-type components. As might be expected, increasing the rolling reduction diminished the effect of penultimate grain size upon rolling. The 50:50 texture transition for 971/2 pct reduction occurred at 0.55 at. pct Sn. Unlike Cu-Zn and Cu-Al alloys, the percentage of brass-type texture reached a maximum at 1.8 at. pct Sn and then decreased for tin contents up to 5.06 at. pct. A self-consistent explanation, based on the “dislocation interaction” hypothesis, has been offered to account for the experimental observations. The present results indicate that the twinning processper se, can actually be detrimental to, rather than promote the formation of the brass-type texture in Cu-Sn alloys.