TA18钛合金管材织构的测试与EBSD分析

用X射线衍射和电子背散射衍射技术,测试了航空用不同规格TA18钛合金管材的织构,并利用织构测试的数据计算了管材的CSR值.由不同规格TA18钛合金管材的(0002)面极图可以得出,管材内部晶粒基面的c轴主要分布在试样RD-TD面内,且沿着ND方向偏转了约30°左右,大部分分布在0～60°的范围之内.利用极图数据所计算的管材的Kearns系数显示,各种规格管材的fr值约为0.6左右,而ft与f1相对较小.同时结合EBSD测试结果,阐述了晶粒形貌与织构产生的原因,对比分析了管材φ6 mm ×0.5 mm横截面与展开面晶粒取向分布特点,结果显示,管材经过多道次的轧制变形,晶粒沿着轧制方向被拉长,试样内部晶粒也出现了明显的择优取向,其中晶粒c轴主要沿ND方向分布,形成了较强的(0002)基面织构.通过EBSD测试方法得到的CSR值与极图计算值和实测值得到的结果相近,因此极图法是一种测试钛合金管材织构的有效方法.     

VAR熔炼TC2钛合金

由于Al、Mn元素在钛合金中的饱和蒸汽压远大于基体元素,因此,TC2钛合金在熔炼中主组元的挥发损失较大,尤其是Mn元素,不利于铸锭化学成分均匀性控制。本文基于活度系数计算模型和控制传质系数计算模型,从热力学角度分析了钛合金熔体中Al、Mn元素的挥发趋势,分析了TC2钛合金中各元素的分布特点,结合生产实际,通过合理控制原材料,选择合适的合金添加剂及熔炼参数等,采用真空自耗电弧炉惰性气体保护熔炼出直径为720mm的TC2钛合金铸锭,结果表明:所熔炼的铸锭径向、轴向化学成分均匀,生产的铸锭经后续加工,所得到的产品均满足标准要求,未出现宏观偏析。     

铝合金板带材多道次轧制中亚晶粒形态和织构的变化

用极图法和透射电镜对纯铝和3003、3004合金在多道次轧制过程中的组织和织构进行了研究。     

可编程序计算器在有择尤取向试样X射线定量分析中的应用

本文为T1—58C和T1—59型可编程序计算器编制一套计算程序,应用于有择尤取向试样的X射线定量分析;并分别采用了Gullberg多线条法以及Mueller和Horta反极图法对Si和ZnO压制试样中Si的衍射强度进行校正,用Zevin无标样法进行定量测定,获得了满意的结果,使繁琐的计算能在几分钟内完成,具有一定的实用价值。     

钛合金的钨极氩弧焊

首先对钛合金做了简单介绍,特别强调钛合金在航空领域的应用,然后通过对钛合金焊接性能的分析,指出钛合金焊接时会产生脆化现象、冷裂纹和气孔问题。最后以8mm厚的TA7钛合金板为例,重点介绍在钨极氩弧焊焊接过程中应如何正确选择焊接工艺参数,应该采取哪些工艺措施保证钛合金的焊接接头质量。     

TC4钛合金板材热轧处理工艺改进研究

钛合金因其具有强的耐腐蚀性能、比强度高、稳定性能好、密度小等优势而应用于各行各业中,但钛合金因其导热率低、变形抗力大、成材率低、轧制成形困难等缺点限制了钛合金的发展。基于此,本文以TC4钛合金板材为研究对象,通过改进热轧工艺,提出TC4钛合金板材的加工安全温度为890℃～1000℃,失稳区范围为700℃～850℃。经过理论仿真模拟计算,本次实测数据与理论计算数据变化规律一致,说明本文所获结论是合理的。     

TC11钛合金相变点的测定与分析

采用计算法、差示扫描量热法和连续升温金相法3种手段计算和测定了TC11两相钛合金（α＋β）/β相变点。计算法由于各元素及杂质元素含量对相变点的影响值是在一个含量范围内的计算值，因此计算的相变点与实测值是接近的；差示扫描量热法由于钛合金和坩埚的化学反应，产生相变滞后现象，导致所测相变温度过高；而连续升温金相法由于淬火温度间隔选择较小，测量的准确性较高，因此更能准确测量TC11钛合金相变温度。通过连续升温金相法，观察不同淬火温度的试样在光学显微镜下的显微组织变化，发现升温过程中初生α相完全消失的温度，从而确定了TC11钛合金的相变点为1035℃。并分析了不同钛合金之间相变点差异的原因。     

基于应力三轴度的TA18钛合金损伤失效研究

对TA18钛合金材料设计不同缺口尺寸的拉伸试样,进行不同应力状态下的室温拉伸试验及断口形貌观察,通过试验和数值计算结合的方法研究TA18钛合金的韧性断裂特性,分析了应力状态对微观断裂机制的影响规律.利用Bridgman正向计算法修正颈缩失稳后的应力数据,建立了TA18钛合金的Johnson-Cook(J-C)本构模型,计算了拉伸试样的平均应力三轴度和断裂应变,回归确定了TA18钛合金损伤失效模型.结果 表明:不同应力状态下的TA18钛合金断裂应变各不相同,断裂应变随着应力三轴度的增大而减小,断口韧窝尺寸与应力三轴度呈正相关关系,所建立的损伤失效模型能够描述该材料的断裂特性.     

延展性高的钛合金

日本一家金属公司生产了一种新型钛合金 ,它的延展性要比普通钛合金高 14%。除了延展性高以外 ,这种钛合金还具有耐高温和强度极高等优点 ,在 30 0℃的高温条件下进行拉力试验 ,它的强度高达 30ｋｇ/ｍｍ2 。新型钛合金是这样制成的 :将一定比例的钼、铝、锡、铬、钒、锆和铁加     

钛合金钎焊

钛合金具有优异的机械性能、焊接性能和耐腐蚀性能,这使得钛和钛合金在航空航天工业和化学工业中的应用不断扩大。钛合金焊接方法的发展对推动钛合金的应用起了重要的作用。经过长期的研究,现已成功地发展了熔化焊(钨极氩弧焊、电子束焊、激光焊、等离子束焊),摩擦焊,扩散焊,钎焊和扩散钎焊。其中钎焊和扩散钎焊主要     

Mechanisms of phase and structural transformations and texture formation in titanium alloy sheet semiproducts

Inverse pole figures are used to analyze texture formation in sheet semiproducts made from titanium alloys of various classes. The role of the mechanisms of phase and structural transformations in texture formation has been revealed. A VT6 alloy is used as an example to study the texture formation during hot, warm, and cold rolling of high-alloy α + β titanium alloys. Hot rolling followed by cooling is shown to form the β → α transformation texture. Warm or cold rolling of α + β titanium alloys leads to the (0001)〈hkio〉 deformation texture of the α phase, and subsequent annealing in the two-phase field results in the transformation texture with a strictly determined orientation distribution of α-phase crystallites due to the shear mechanism of α-phase nucleation. Specifically, the 〈10\(\overline 1 \)0〉 orientation is parallel to the rolling direction, the [0001] direction is parallel to the transverse direction, and the {11\(\overline 2 \)0} planes are parallel to the rolling plane. Thermohydrogen treatment in combination with rolling is shown to form nano-and submicrocrystalline structures with a virtually textureless α phase in VT6 sheet semiproducts. As a result, the anisotropy of the mechanical properties of the sheet semiproducts produced by this new combined hydrogen technology decreases sixfold.     

Use of the impulse technique for rapid texture evaluation in commercial tube and plate materials

A simple, rapid method for the nondestructive evaluation of texture in metal sheet of arbitrary thickness is presented. The method uses a recently developed technique to generate and receive Rayleigh waves on thick plates or Lamb waves on thin materials. The correlation of Rayleigh wave velocity data with calculated values based on elastic constant measurements and with X-ray pole figures is discussed in detail. The technique is applied to a variety of commercially important materials and geometries by the generation of “ultrasonic pole figures.”     

我国钛及钛合金板材标准化现状

主要回顾了我国钛及钛合金板材标准化历程,重点介绍了本世纪钛板材国标体系的重要变化及完善情况,并与国外先进标准进行了对比,提出了进一步完善和发展我国钛板材标准体系的发展思路、改进意见和建议。     

SP700钛合金薄板超塑性研究

研究了2种不同工艺对SP700钛合金薄板的超塑拉伸性能的影响,并测试了SP700钛合金薄板可达到的最大超塑性能.结果 表明:采用最大m值超塑变形拉伸试验法,在775℃可得到SP700钛合金薄板试样的最佳超塑性能,超塑性可以达到3000％以上.     

Determination of the total texture

The orientation distribution function (ODF) calculation is usually performed using pole figures measured by X-ray or neutron diffraction. However, this kind of experimental technique does not allow total ODF to be determined, since the odd terms of the series expansion are not directly accessible from pole figures. The individual orientation measurement technique can be used, but it is necessary to evaluate the right orientation number necessary for a statistically reliable ODF. For samples at the surface, at the fifth of thickness from the surface and at the center of a Fe 3 pct Si sheet, this study shows that only 100 orientations are sufficient to find the principal components of the texture, but this number must be increased by a factor of 10 to evaluate with rather good accuracy the heights of the peaks. Indeed, to obtain a good correlation with an ODF calculated from pole figures measured by X-ray diffraction, the number of orientations needed is about 1000.     

Methodological aspects of the quantitative texture analysis of HCP Alloy (Ti,Zr) sheet semiproducts

The specific features of the existing methods of quantitative texture analysis of semiproducts and products made of titanium and zirconium alloys are analyzed. A technique is proposed to determine the Kearns coefficients (f parameters) for sheets made of hcp-metal-based alloys with allowance for the weighting factor of each reflection in the standard stereographic triangle. The f parameters calculated for sheets made of a zirconium alloy and various titanium alloys using different techniques are compared. The accuracy of measuring the Kearns coefficients by the inverse pole figure method is estimated.     

TC4包复叠轧薄板组织与性能特征

对TC4薄板包复叠轧及单片轧制工艺生产板材取样分析，研究了包复叠轧产品性能、显微组织、极图、ODF织构等的特征，数据表明包复叠轧产品具有组织和性能各向异性小，塑性好，利于超塑成形的特点。     

TA1钛合金板材洛氏硬度B标尺试验分析

TA1钛舍金板材洛氏硬度B标尺试验结果不合格较多,检测中心与薄板车间试验结果差异较大。文章针对这种结果争议,通过试验验证找到数据存在差异的原因,并对如何更标准地进行钛合金板材洛氏硬度B标尺试验．提出有效的、良好的操作建议。     

Physical asymmetry of the crystallographic

The texture of a mill-produced, Nb-bearing, interstitial-free, hot-rolled sheet steel was evaluated at a number of sheet thickness positions. The texture was also studied following laboratory cold rolling and following recrystallization. A “nonsymmetric case” crystallite orientation distribution function analysis applicable to the analysis on nonsymmetric pole figures was used. While sheet steels are generally assumed to have orthotropic physical symmetry, it was found that an appreciable degree of physical asymmetry existed. The asymmetry was with respect to the rolling direction (RD) and normal direction (ND) mirror planes, while transverse direction (TD) mirror-plane symmetry existed.