冷轧形变量对异步轧制高纯铝箔织构的影响

应用取向分布函数(ODF)研究和分析了异步轧制高纯铝箔的形变织构和再结晶织构.结果表明:异步轧制高纯铝箔的形变织构除了C{112}<111>、B{110}<112>和S{123}<634>织构组分外,还有较强的CubeND{001}<110>和{102}织构.异步轧制高纯铝箔的再结晶织构由强的立方织构{001}<100>和弱的R{124}<211>织构组成.随着形变量的增加,异步轧制高纯铝箔的形变织构和再结晶织构呈现规律性的变化,{102}织构减少,S织构先增后减,速比较小时C织构近线性减少,速比较大时C织构则先增后减.异步轧制高纯铝箔的退火样品中有很强的立方织构,这与异步轧制提高高纯铝箔的形变储能有关,形变量过大时,立方织构随形变量的增加急剧减少.{102}织构有利于再结晶立方织构的加强.     

常化退火处理对无取向硅钢组织和织构的影响

采用光学显微镜和X射线衍射仪研究了常化退火处理对无取向硅钢热轧板和成品退火板显微组织和织构的影响。结果表明:常化退火处理消除了热轧板中的变形组织,促使变形晶粒完成再结晶;常化退火处理使高斯织构和立方织构易通过再结晶在变形带内形核和长大,可显著降低成品退火板的{111}和{112}不利织构组分的占有率,提高{100}和{110}有利织构组分的占有率,从而有利于提高无取向硅钢成品板的磁性能。     

镁合金搅拌摩擦焊接头晶粒取向和织构分析

利用背散射电子衍射分析技术(EBSD)和取像显微分析技术(OIM),通过定量测量变形镁合金AZ80A搅拌摩擦焊搭接接头的焊核区晶粒取向和织构,探讨了搅拌摩擦焊焊核区形成的微观过程.结果表明:AZ80A合金在搅拌摩擦焊过程中,存在塑性变形和动态再结晶两种微观过程,导致焊核区所形成的晶粒织构密度不强、取向呈多样化的趋势;晶粒为再结晶细晶粒;在焊核区,变形织构{1,-1,0,4}<1,0,-1,0>略偏离板法向20°,且随板厚方向向下越来越强,同时再结晶取向越来越多;焊核区晶粒继承了母材中的{1,-1,0,4}<1,0,-1,0>变形织构,在焊核区所发生的动态再结晶含有一定程度的原位再结晶.     

轧制温度对双辊铸轧硅钢形变与再结晶织构的影响

采用宏微观织构分析相结合的方法,研究了轧制温度对双辊铸轧Fe-2.8%Si-0.8%Al硅钢形变与再结晶织构的影响。室温和200℃轧制样品形变织构均由α(〈110〉∥RD)、γ(〈111〉∥ND)和λ(〈001〉∥ND)纤维织构组成,但200℃轧制显著减弱α、λ形变织构,增强γ形变织构特别是1/4层的{111}〈110〉织构。200℃轧制时,剪切带数量增多、储能增强,从而促进了Goss({110}〈001〉)、Cube({001}〈100〉)再结晶晶粒分别在γ和{111}〈110〉形变基体剪切带的大量形核,γ再结晶晶粒在晶界少量形核以及Goss和Cube再结晶晶粒的增多,有效抑制了γ织构。λ织构的变化由Cube和{001}〈110〉的变化共同决定,在1/4层,Cube织构显著增强导致λ织构的增强;在中心层,Cube略微增强而{001}〈110〉显著减弱导致λ织构的减弱。     

时效工艺对6061铝合金力学性能各向异性的影响及微观组织研究

采用单向拉伸试验研究了经不同时效工艺处理的6061铝合金轧制板材在轧制方向(0°)、倾斜方向(45°)和横向(90°)的力学性能各向异性.实验结果表明,轧制态6061铝合金的力学性能与热处理工艺密切相关,且表现出明显的各向异性.其中T6态6061铝合金力学性能各向异性最不明显.轧制态6061-T6铝合金有较强的立方织构{001}〈100〉和较弱的织构成分{001}〈100〉,目前采用的人工时效方法对其晶粒的显微组织和织构演化的影响不大.相对于经其他工艺处理的轧制态6061铝合金,经240℃高温时效处理的轧制态6061-T6铝合金位错密度大,且分布更均匀.轧制态6061-T6铝合金中明显的高密度β″析出物是其具备最高强度和最低各向异性的主要原因.     

GH4169合金楔横轧加工过程中动态再结晶及织构演变

为研究GH4169合金楔横轧加工过程中动态再结晶及织构演变规律,采用金相显微镜(OM)和电子背散射衍射(EBSD)对30%,50%两种断面收缩率下GH4169合金楔横轧件表层与心部的微观组织、晶体取向及织构进行分析。结果表明:GH4169合金楔横轧加工过程中,随着动态再结晶的发生,晶体取向逐渐变得随机化分布;轧制表层大角度晶界数量较轧件心部多,轧件表层织构强度变化不大,心部织构强度明显增强;经过楔横轧变形后织构发生转动,原始态织构类型为{001}〈110〉,{111}〈110〉,{111}〈011〉,轧制后主要织构类型为{001}〈010〉,{112}〈110〉,{110}〈111〉,{110}〈112〉;GH4169合金楔横轧件动态再结晶及织构演变规律是由楔横轧特殊变形特点决定的。     

轧制方式对工业包装铝合金板材微结构 及各向异性的影响

为了获得工业包装用高强高韧铝合金材料,采用喷射成形快速凝固技术和大压下量轧制技术制备了Al-9Mg合金板材。采用透射电镜、扫描电镜(采用EBSD技术)和X射线衍射仪测定了挤压态和轧制态Al-9Mg合金板材的微结构及织构特征,并测试了板材的各向异性行为。试验结果表明:大压下量交叉轧制CBA促进了动态再结晶的发生,细化了晶粒组织,显著提高了大角度晶界的比例;与挤压态和AAA轧制方式相比较,CBA轧制方式显著降低了挤压态合金中典型的Brass织构{110}112的取向密度,在β取向线上CBA轧制态板材中的Brass织构取向密度最低,且板材中没有典型的织构特征;同时,CBA轧制态合金板材具有更好的深冲性能,在3个方向0°,45°和90°的力学性能基本一致,其室温拉伸强度和伸长率分别在592MPa和19.6%以上。     

Fe-Ga-B合金室温塑性及轧制材料磁致伸缩性能

研究了0.5%(原子分数)B对Fe83 Ga17合金室温力学性能的影响及(Fe81 Ga19)99.5 B0.5轧制薄片磁致伸缩性能.结果表明,少量B添加提高了Fe-Ga合金的室温塑性,实现(Fe81 Ga19)99.5 B0.5合金的轧制成形.热处理对(Fe81 Ga19)99.5 B0.5合金薄片材料磁致伸缩性能有很大影响.在同一热处理制度条件下,磁致伸缩性能随变形量的增加而减小;对于变形量为93.5%的样品,同一热处理时间,样品磁致伸缩性能随热处理温度的升高而增加,同一热处理温度时,样品磁致伸缩性能都表现出先升高后降低的变化趋势,样品在1300℃保温2h后,磁致伸缩性能最好,达到1.65×10-4.热处理对(Fe81 Ga19)99.5 B0.5合金薄片材料磁致伸缩性能的影响归因于对样品织构的影响.具有{100}＜012＞织构样品的磁致伸缩性能最高,而{111}＜110＞和{111}＜112＞织构对应的磁致伸缩性能较低.     

冷轧纯铜微观组织及织构演变的特征

介绍了电子背散射技术（EBSD）在材料织构方面的研究应用状况,并采用EBSD研究了纯铜在冷轧过程中晶粒的变化、晶粒取向及晶界角度分布的特征。结果表明,纯铜在经过大变形量后出现轧制织构,其轧制织构主要是{112}〈111〉和{011}〈112〉织构;在中小变形量下,随着变形量的增加大角度晶界逐渐减少,而到高变形量时逐渐增加。     

同步、异步组合轧制取向硅钢极薄带的织构研究

采用同步、异步组合轧制方式将成品工业取向硅钢板冷轧到0.08mm,然后在纯氢气炉中高温退火,采用ODF和反极图定量分析硅钢薄带的冷轧和再结晶织构。研究结果表明,在同步、异步组合轧制方式下,冷轧薄带的变形织构与一般常规冷轧板的相同,但沿板厚呈现了不对称分布,经840℃保温6h退火,晶粒取向为集中的{110}〈001〉。     

Estimation of Parameters of Universal Distribution of Moments of Failure of Products

A method is proposed for estimating the parameters of a mixture of exponential and Weibull distributions for which the accuracy of preliminary estimates obtained by graphical analysis is refined in accordance with the criterion of maximum likelihood. The efficiency of the proposed method is supported by the results of statistical modeling.     

Evaluation of optical properties of highly scattering media by moments of distributions of times of flight of photons

A novel method for the determination of the optical properties of tissue from time-domain measurements is presented. The data analysis is based on the evaluation of the first moment and the second centralized moment, i.e., the mean time of flight and the variance of the measured distribution of times of flight (DTOF) of photons injected by short (picosecond) laser pulses. Analytical expressions are derived for calculation of absorption and of reduced scattering coefficients from these moments by application of diffusion theory for infinite and semi-infinite homogeneous media. The proposed method was tested on experimental data obtained with phantoms, and results for absorption and reduced scattering coefficients obtained by the proposed method are compared with those obtained by fitting of the same data with analytical solutions of the diffusion equation. Furthermore, the accuracy of the moment analysis was investigated for a range of integration limits of the DTOF. The moment analysis may serve as a comparatively fast method for evaluating optical properties with sufficient accuracy and can be used, e.g., for on-line monitoring of optical properties of biological tissue.     

Estimation of potentialities of methods of summation of direct measurement errors

Conventional methods for summation of direct measurement errors are considered. Conditions under which these methods provide consistent results are stated. It is proposed to utilize for characteristic of the total error, its interval estimator or the half-sum of the value obtained by adding up its arithmetic and geometric random errors.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 10–12, April, 1995.     

Analysis of the rate of propagation of the wave of change of boiling modes

An approximate analytical expression is derived for the velocity of the front of the wave of change of boiling modes on a rod and on a plate. The impact of the Thomson effect and of the heater orientation in the gravity field is included. Adequate agreement is demonstrated between the derived relations and experimental data.     

空压机轴承箱蜗壳温度探头油封改造

由于空压机进气侧轴承箱蜗壳温度探头密封效果不好,使空压机及其后续管道受到油污染。后将温度探头的O形圈密封改为骨架油封,杜绝了轴承箱漏油问题。文章简介空压机的结构和技术参数,详细介绍了骨架油封的制作和优点。     

Characteristics of mechanical properties of materials in studies of conditions of attainment of marginal states

It is shown that conditions of attainment of marginal states in the material of structural components are formulated on the basis of analysis of force and deformation criteria of formation and development of destruction. The parameters of these criteria are data on types of structural materials, standard and special characteristics of their mechanical properties, structural forms of considered elements of the equipment, and their operating stress loading. In this case, the construction of a system of state equations for describing interrelation of current damage, external actions, and responses to them is based on the concept of calculating variations in properties of materials at all stages of the design life cycle.     

Determination of parameters of microstructural inhomogeneity of deformation of metals by the method of modeling

The article suggests a method of evaluating the microstructural inhomogeneity of deformation of metals by modeling. The method includes the measurement of deformations of metal according to meshes of a dividing grid with small base and the calculation of the distribution parameters of microdeformations in model representation. It is shown that the modeling method makes it possible objectively to evaluate the microinhomogeneity of deformation of metals independently of the chosen mesh size of the dividing grid. New structural characteristics are introduced: the base and wave of variation expressing the degree of crumbling or amalgamation of metal grains by inhomogeneity of deformation.Translated from Problemy Prochnosti, No. 7, pp. 40–44, July, 1991.     

水三相点复现的不确定度评定

水三相点是开尔文热力学温度的唯一基准点，也是ITS-90国际温标重要的定义固定点。因此，水三相点不确定度分析对整个温标的建立、温度量值传递起着至关重要的作用。近3年来，中国计量科学研究院研制出一系列高质量的水三相点容器，加强了水三相点的研究，为不确定度的分析提供了更为可靠的实验依据。同时，不确定度的分析也是客观评价新研制容器性能的一个重要指标。因此，根据实验结果对新研制容器所复现的水三相点进行了不确定度评定。评定结果表明，其扩展不确定度为0．16mK(k=2．69，P=0．99)。