共查询到20条相似文献,搜索用时 15 毫秒
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M. S. Yeh C. B. Chang T. H. Chuang 《Journal of Materials Engineering and Performance》2000,9(1):51-55
Although intimate contact can be obtained for diffusion bonding of a superplastic Inconel 718SPF superalloy under a low pressure
of 7 MPa, the precipitates formed at the interface retarded achievement of a sound joint. The shear strength was only 41.5
MPa for an overlap length of 12 T (T=1.3 mm, sheet thickness). The diffusion bondability of this Inconel 718SPF superalloy was enhanced by electroless nickel
plating. In this situation, the bonding shear strength increased to 70.4 MPa for the same overlap length of 12 T under the same bonding condition, regardless of the roughness of the surface to be bonded. Upon decreasing the overlap length
from 12 to 6 T, the bonding strength remained constant. 相似文献
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《中国有色金属学会会刊》2021,31(12):3762-3771
Solidification behaviors of Pt-containing 718Plus superalloyswere studied by scanning electron microscopy (SEM), energy dispersive spectrum (EDS), differential scanning calorimetry (DSC) and simulation calculations. It is found that Pt increases solidification range and decreases solidus temperature of the alloy and precipitation temperature of Laves + γ eutectic phase since Pt enlarges the region of γ phase by increasing Nb solubility. In addition, Pt segregates to the interdendritic region and increases the segregation of Nb and Tiin the interdendriticregion due to the strong attractive interactions between Pt and Nb/Ti. As a result, Pt promotes the precipitation of the Laves + γ eutectic phase and η phase around eutectic phase. The increase of solidification range and segregation degrees of Nb and Al caused by Pt also promotes the precipitation and growth of γ’ + γ” phase around eutectic phase. These results provide experimental bases for understanding the mechanism of Pt in solidification behavior of superalloys. 相似文献
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INCONEL718高温合金均匀化处理的定量分析 总被引:1,自引:0,他引:1
利用定量分析手段建立INCONEL718高温合金的均匀化模型.采用金相法确定d406 mm铸锭的初熔温度,结果表明其初熔温度为1 170~1 180℃.采用两阶段均匀化热处理消除枝晶显微偏析.为了定量预测Laves相的溶解过程,提出一个和时间、温度相关的均匀化模型.在铸态组织的所有偏析元素中,Nb和Ti为偏析程度最大的正偏析元素.然后,分别计算在1 140℃时各合金元素的扩散系数,并与另外两种常见的含铌高温合金进行比较. 相似文献
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以超高转速等离子旋转电极法(SS-PREP法)制备的高球形度Inconel 718高温合金粉末为原料,采用热等静压(HIP)工艺制备了Inconel 718粉末高温合金,重点研究了热处理制度对合金组织和力学性能的影响.实验结果表明:采用SS-PREP法制得的Inconel 718高温合金粉末粒度分布均匀,球形度良好,具... 相似文献
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在Gleeble-3500热模拟实验机上对Delta工艺Inconel 718合金进行高温压缩实验,研究其高温压缩变形的流变应力行为。结果表明:δ相时效态Inconel 718合金在本实验条件下具有正的应变速率敏感性,流变应力随着应变速率的降低和变形温度的升高而减小,动态再结晶是合金重要的软化机制。δ相时效态Inconel 718合金的热变形激活能为497.407 kJ/mol,高温压缩峰值流变应力与变形温度和应变速率的关系可用双曲正弦函数表示。 相似文献
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Strain-rate hardening behavior of superalloy IN718 总被引:4,自引:0,他引:4
J. M. Zhang Z. Y. Gao J. Y. Zhuang Z. Y. Zhong P. Janschek 《Journal of Materials Processing Technology》1997,70(1-3):252-257
In order to produce superior feed stock for the forging of turbine disks and other components, it is necessary to better understand the effect of deformation parameters on the hot deformation behavior of IN718 during thermomechanical processing. Superalloy IN718 is a strain-rate sensitive material. In the present work, isothermal constant speed compression tests of superalloy IN718 were conducted using a computer-controlled MTS machine at temperatures of from 960 to 1040°C, with initial strain rates of from 0.001 to 1.0 s−1, to engineering strains of from 0.1 to 0.7. The variation of flow stress with initial strain rate was analyzed in the paper. It was found that there was an obvious power-law relationship between flow stress and initial strain rate. From the results of these tests, a mathematical model showing the strain-rate hardening behavior of superalloy IN718 at elevated temperatures was developed. At the same time, the flow stress calculated from the model was compared with experimental results and the effect of deformation parameters on the related coefficients was analyzed. 相似文献
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X. D. Ding H. M. Zbib C. H. Hamilton A. E. Bayoumi 《Journal of Materials Engineering and Performance》1995,4(4):474-485
The superplastic blow-forming process of thin sheets is analyzed, and an optimal stable deformation path that reduces production
time is obtained. The analysis is based on an analytical model for the superplastic forming (SPF) of a long rectangular box
made of Ti-6Al-4V alloy at 900 °C use of a microstructure-based constitutive equation for the strain rate and grain growth,
a stability criterion, and a variable strain rate control. It is shown that by imposing a variable strain rate control scheme
derived from the stability analysis, an optimal forming time can be developed while maintaining a stable deformation path.
Some other control schemes also show effectiveness in either reducing the localized thinning in the formed sheet or reducing
the required forming time. Effects of friction and initial grain sizes on the forming pressure profile and the thickness distribution
of the formed sheet are also investigated. 相似文献
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对Inconel 718高温合金12mm厚板的真空电子束焊(EBW)接头整体及分层的显微组织和高温力学性能进行了研究。结果表明:经熔透焊+修饰焊的接头,焊缝中心的上、下层为树枝晶,中层为柱状晶;热影响区由上层至下层晶粒长大程度逐渐减小。经固溶+双时效热处理后,EBW接头各区域晶界处均有δ相析出,在焊缝中心最多,在热影响区及母材较少,晶粒内部均析出了γ″相。在650℃时,接头整体的抗拉强度σb、屈服强度σs和伸长率δ分别为1100MPa、800MPa和18%,达到了母材的90%、80%和80%。分层切片的力学性能下层最高,σb、σs和δ分别达到了1170MPa、870MPa和18%;上层最低,分别为1080MPa、780MPa和7%。上层断口以脆性断裂为主,中、下层断口以韧性断裂为主。显微硬度分布为焊接中心最低,热影响区与母材较高。晶界δ相的析出数量越多,显微硬度值越低。 相似文献
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1.IntroductionSurfaceandinterfacialsegregationiscurrentlyaveryactiveareaofresearch.Thisphenomenonhasbeenstudiedextensivelyinbinaryandternaryalloysll--31.Commercialsteelsandsuperalloysarecomplexsystemswithmanyelementalspecies.Whileimpuritysegregationhasbeenwidelystudiedinsteels,comparativelylittleisknownaboutthesuperalloys.Cleansuperalloyproductionisvanguardofthesuperalloyindustryandcleanlinesshasbeenbasicallyconsidetedintwocategories:inclusionsanddetrimentalelementsco.t.oll4].Sulfurandphospho… 相似文献
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Study on wear mechanisms in drilling of Inconel 718 superalloy 总被引:4,自引:0,他引:4
The wear mechanisms and the approach to prolong the service life of the TiAlN coated carbide tool in drilling Inconel 718 superalloy are presented. It is found that the coated layer on the cutting edge is gradually abraded-off at the first stage of drill wear due to an excessive friction force on the tool–work interface. This in turns intensifies the friction force and leads to an increase of drilling force. Built-up edge (BUE) is then formed, and chipping starting from the relatively weaker cutting edge takes place subsequently. As a result, many micro-cracks are observed to distribute over the worn area. The subsurface fatigue cracks grow as the drilling process is proceeding. Together with the abrasion of hard carbide particles of the work material, the cutting edges break eventually parallel to the direction of fatigue cracks. At this moment, longer chip forms and cutting process is disturbed to an extent that the process can no longer be effectively continued. Failure of the drill is noted in a very short period of time once the long chips are observed. Finally, drilling experiments with the use of the cutting fluid containing the nano-particle low friction surface modifier are conducted. It is found that the service life of the drill is lengthened significantly and hence the machining cost can be greatly reduced. 相似文献
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Overview of superplastic forming research at ford motor company 总被引:1,自引:0,他引:1
Friedman P. A. Luckey S. G. Copple W. B. Allor R. Miller C. E. Young C. 《Journal of Materials Engineering and Performance》2004,13(6):670-677
In an effort to reduce vehicle weight, the automotive industry has switched to aluminum sheet for many closure panels. Although
the application of aluminum is compatible with existing manufacturing processes and has attractive qualities such as low density,
good mechanical properties, and high corrosion resistance, it has less room-temperature formability than steel. The expanded
forming limits that are possible with superplastic forming can significantly improve the ability to manufacture complex shapes
from materials with limited formability. Aluminum closure panels produced by superplastic forming have been used by Ford Motor
Company for over a decade. However, applications have been limited to low-volume, specialty vehicles due to the relatively
slow cycle time and the cost penalty associated with the specially processed sheet alloys. While there has been substantial
research on the superplastic characteristics of aluminum alloys, the bulk of this work has focused on the development of aerospace
alloys, which are often too costly and perhaps inappropriate for automotive applications. Additionally, there has been a limited
amount of work done to develop the technologies required to support the higher production volumes of the automotive industry.
This work presents an automotive perspective on superplastic forming and an overview of the research being performed at Ford
Motor Company to increase the production volume so superplastic forming can be cost competitive with more traditional forming
technologies.
This paper was presented at the International Symposium on Superplasticity and Superplastic Forming, sponsored by the Manufacturing
Critical Sector at the ASM International AeroMat 2004 Conference and Exposition, June 8–9, 2004, in Seattle, WA. The symposium
was organized by Daniel G. Sanders, The Boeing Company. 相似文献
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CONSTITUTIVERELATIONSHIPOFSUPERALLOYIN718J.M.Zhang;L.Z.Ma;J.Y.Zhuang;Q.Deng;J.HDuandZ.YZhong(DepartmentofSuperalloys,CentralI... 相似文献
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纳米陶瓷的热压烧结及超塑成形(英文) 总被引:2,自引:0,他引:2
纳米陶瓷具有优良的室温和高温力学性能 ,如较高的抗弯强度、断裂韧性、耐磨性等 ,使其在切削刀具、轴承、高温发动机部件等诸多方面都有广泛的应用。利用纳米陶瓷的超塑性进行成形加工是实现复杂形状零件近净成形的重要手段。本文采用化学沉淀法制备了平均粒径 10nm ,且无硬团聚的 3Y TZP (3%摩尔氧化钇稳定的四方相氧化锆多晶体 )粉体 ,研究了不同密度素坯的热压烧结行为。 3Y TZP毛坯的超塑性拉深试验表明在 14 5 0℃压头速率为 0 2mm·min-1时可以实现半球形件的成形 ,其成形高度达到 5 7mm ;Al2 O3 ZrO2 纳米复相陶瓷的正挤压试验表明 ,这种典型的晶间 /晶内型纳米陶瓷在很高的温度下可以 0 . 5mm·min-1的压头速率进行挤压成形 ,在某种程度上可以满足工业成形的需求 ;Si3 N4 Si2 N2 O复合陶瓷通过烧结锻造可以成形陶瓷齿轮 ,其烧结温度为 16 0 0℃ ,超塑性锻造温度为 15 5 0℃。 相似文献
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利用选区激光熔化成形技术于激光扫描速度800~1100 mm/s范围内制备了718HH塑料模具钢试样。采用光学显微镜、扫描电镜和半自动显微硬度计研究了激光扫描速率对选区激光熔化成形718HH塑料模具钢试样成形质量、显微组织和显微硬度的影响规律。研究表明,随着扫描速率的增加,成形件内部孔洞的数量增多、尺寸变大,且侧表面边界出现不同程度的裂纹;腐蚀后的成形件,其组织主要由马氏体组成,侧表面可以观察到典型的熔池形貌,且随着扫描速率的增大,熔池分布越来越不均匀;成形件具有较高的显微硬度,由于晶粒尺寸、残余应力以及孔洞裂纹等缺陷的综合影响,成形件的平均显微硬度随着扫描速率的增加呈现先升高后降低的趋势。当扫描速率为800 mm/s时,成形件内部几乎没有孔洞和裂纹等缺陷,成形组织致密,且具有良好的显微硬度,适用于718HH模具钢的选区激光熔化成形。 相似文献
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MICROSTRUCTURE AND MECHANICAL PROPERTIES OF NOVEL 718 SUPERALLOY 总被引:2,自引:0,他引:2
Recently, a novel 718 superalloy with remarkable structural stability at 680℃ has been designed and fabricated by CISRI (Central Iron and Steel Research Institute) etc. Phase identification of novel 718 alloy under the above-mentioned heat-treatment condition was performed using optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Results show that the novel 718 alloy has outstanding structural stability at 680℃. The novel 718 alloy possess excellent structural stability and good mechanical properties, which is attributed to ?酌'-phase strengthening and also to the specific sandwich structure of the ?酌' + ?酌' strengthening phase. 相似文献
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H. G. Salem A. P. Reynolds J. S. Lyons 《Journal of Materials Engineering and Performance》2004,13(1):24-31
Friction stir welding was used to join superplastic AA 2095 sheets. The effect of welding rate on the grain size distribution
and grain boundary misorientations in the stir zone was investigated. The superplastic behavior of the weld nugget parallel
to the welding direction was also characterized at 495 °C and strain rates from 10−4s−1 to 10−2s−1. Increasing the welding rate during friction stir welding augmented the formation of a fine-equiaxed high-angle grain boundary
structure within the stir zone. Increasing intensity of plastic straining during friction stir welding resulted in enhanced
properties during subsequent superplastic formation. The maximum strain-to-failure was obtained for the weld made at a tool
speed of 1000 rpm and a weld rate of 4.2 mm/s when tested at a superplastic forming strain rate of 10−3s−1. 相似文献
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以非晶氮化硅纳米陶瓷粉体为初始材料,以纳米氧化钇和氧化铝为助剂液相烧结获得超塑性陶瓷块体材料,在1550℃的低温条件下,实现氮化硅陶瓷的超塑性成形。利用描述超塑性材料的Backofen方程,建立陶瓷超塑性成形的刚粘塑性有限元模型,并与实验研究相结合,研究氮化硅陶瓷在不同条件下超塑性拉深成形过程中,成形体径向和厚度方向的尺寸变化,得到了氮化硅陶瓷超塑性拉深成形过程厚度和径向尺寸改变的基本规律。 相似文献
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回顾了王仲仁教授在超塑性研究领域的一系列重要研究成果。Sn-Pb共晶超塑性材料薄壁管复合加载实验表明,在复杂应力状态下超塑材料遵守Mises屈服准则,并与Tresca屈服准则也接近,给出了超塑材料在应变速率强化条件下的屈服轨迹;研究了超塑变形过程中晶粒和孔洞的长大规律及其对变形中流动应力的影响,导出了包含晶粒长大和孔洞长大影响的超塑性本构关系;提出了测定超塑材料摩擦系数的理论校准曲线和应变速率敏感性指数的变截面拉伸试验法;开发了带有动凸模的微机控制的1000kN超塑成形机,研制了当时国内最大的微机控制的5000kN超塑成形机;在模具型腔超塑成形研究方面,成功挤压了130型汽车连杆锻模,是迄今为止尺寸最大的超塑成形模具钢型腔。 相似文献