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1.
《Surface & coatings technology》1986,28(1):39-55
A new method for the calculation of residual stress in the cross section of an electrodeposit formed on one of the sides of a bending strip cathode is proposed. The relations for the cases of deposition and of dissolution of the deposit are given. In addition, suitable conditions for verification of the numerical values obtained are proposed. An example is given to show the advantages of the new method over previous methods. A precise relation is derived for determining the average residual stress in the cross section of the deposit. 相似文献
2.
首先对50mm厚TA15钛合金平板分别采用堆焊和对焊两种方法进行电子束焊接,然后采用盲孔法测量了热处理和未热处理情况下焊接试件残余应力的分布情况.测量发现,对接焊和堆焊试件上表面纵向应力在焊缝和热影响区呈现较大的拉应力,且对接焊试件的纵向应力大于堆焊试件;上表面横向残余应力幅值较低,且整体呈现压应力分布.下表面的横纵应力整体上为压应力,且横纵应力的分布和大小非常接近.结果表明,热处理工艺造成各试板的横纵应力趋于一致,整个试板上的应力趋于均匀化,且堆焊试件的均匀化程度更明显. 相似文献
3.
In this report, an optimised method for residual stress determination at the microscopic scale is presented. The newly proposed approach involves incremental Focused Ion Beam (FIB) milling of annular trenches at material surface, combined with high resolution SEM imaging of a previously deposited marker pattern. Digital image correlation (DIC) analysis of the relative displacements between markers with respect to the undisturbed state provides a measure of strain relief. Results of finite element modeling show that the proposed configuration gives complete strain relief when the annular trench depth becomes comparable with the diameter of the remaining stub, thus allowing analytical calculation of the average residual stress from measured strain components. Basing on results of modeling, the experimental methodology has been developed and optimised for residual stress analysis in thin coatings. In order to cover a wide range of material properties and residual stress states, two different materials have been selected: TiN CAE-PVD coating (hard and stiff, with compressive residual stress) on WC-Co substrate, and also an Au MS-PVD coating (soft and compliant, with tensile residual stress). The procedure for the optimization of FIB milling parameters is reported. Results are validated by comparison with residual stress evaluation by X-ray diffraction and curvature measurement on the two different specifically selected PVD coatings. 相似文献
4.
R. Gadow M. J. Riegert-Escribano M. Buchmann 《Journal of Thermal Spray Technology》2005,14(1):100-108
Residual stresses are related to the thermophysical properties of substrate and coating materials and occur after the coated
component has undergone thermal spraying and machining processes. All residual stresses in layer composites result from different
individual stress mechanisms occurring during the manufacturing process, mainly based on heat and mass transfer during the
coating deposition. Using the hole-milling-and-drilling method, residual stress fields can be measured in a quasi-nondestructive
way over the drilling depth with appropriate resolution. In several drilling and milling operations, a cylindrically shaped
hole is brought step by step into the component surface. The residual stresses are locally relieved due to material removal,
deform the surface around the drilled microhole, and are measured by high-resolution measurement tools (e.g., strain gages
(DMS)), for every drilling step in the form of relaxed surface strains. Using calibration curves and material data (E, μ), the measured surface strains are converted into nominal strains at the bottom of the drilled hole for every drilling
step. Out of the differentiated strains, in-plane stress fields can be incrementally determined by Hooke’s law. This study
describes residual stress measurement features, the finite-element method (FEM) calculation, and the idealization of calibration
curves, as well as the results of exemplary stress measurements.
The original version of this article was published as part of the ASM Proceedings, Thermal Spray 2003: Advancing the Science and Applying the Technology, International Thermal Spray Conference (Orlando, FL), May 5–8, 2003, Basil R. Marple and Christian Moreau, Ed., ASM International,
2003. 相似文献
5.
The residual stress distribution in the surface region of solution treated and aged 7075 aluminium alloy workpieces that are orthogonally burnished under lubricated condition is determined using a deflection etching technique. The residual stress at the surface is low compressive and increase rapidly with an increase in depth beneath the burnished surface to a maximum compressive then decreases gradually with further increase in depth becoming vanishingly small tensile or compressive. The maximum residual stress and depth of the stressed region increase in burnishing speed, force and an increase, to some extent, in burnishing time. The results are interpreted qualitatively in terms of the variations in the amount of surface region deformation produced by changes in burnishing conditions. 相似文献
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《Science & Technology of Welding & Joining》2013,18(2):185-192
AbstractThe authors investigate the efficacy of applying rolling pressure along the weld line in thin butt welds produced using friction stir welding (FSW) as a means of controlling the welding residual stresses. Two cases are examined and in each case, comparison is made against the as welded condition. First, for FSW of AA 2024 aluminium alloy, roller tensioning was applied during welding using two rollers placed behind and either side of the FSW tool. Very little effect was seen for the down forces applied (0, 50, 75 kN). Second, for FSW AA 2199 aluminium alloy, post-weld roller tensioning was applied using a single roller placed directly on the FS weld line. In this case, significant effects were observed with increased loading, causing a marked reduction in the longitudinal tensile residual stress. Indeed, a load of just 20 kN was sufficient to reverse the sign of the weld line residual stress. Only slight differences in Vickers hardness were observed between the different applied loads. Furthermore, unlike some methods, this method is cheap, versatile and easy to apply. 相似文献
8.
J. Toribio 《Journal of Materials Engineering and Performance》1998,7(2):173-182
This paper describes a wide variety of residual stress effects in stress-corrosion cracking (SCC) of metallic materials on
the basis of previous research of the author on high-strength steel in the form of hot-rolled bars and cold-drawn wires for
prestressed concrete. It is seen that internal residual stress fields in the material play a very important—if not decisive—role
in the SCC behavior of any engineering material, especially residual stresses generated near the free surface or in the vicinity
of a crack tip. 相似文献
9.
The residual stress generated in the laser cladding could lead to undesirable distortions or even crack formation.In order to better understand the evolution/yielding process of stress field,a 3D finite-element thermo-mechanical model was established for the laser cladding formation of thin wall with the 17 -4PH powder on the FV520(B)steel.The temperature field was firstly analyzed,based on which the stress field and strain field of the laser cladding forming process were analyzed.In order to validate the prediction,the final residual stress field in the obtained thin wall was tested by X-ray diffraction in comparison with the predicted results. 相似文献
10.
The residual stress distributions of ZrO2/NiCoCrAlY high-temperature coatings were analyzed using an analytical model and finite element analysis. Three different topics were involved, namely the effect of interlayer on the stress distribution, the zero-deflection design for typical duplex-layer thermal barrier coating-based system, and the edge effect on the residual stress distribution. These topics could provide some insights into the development of a fail-safe design methodology for high-temperature coating systems. 相似文献
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A. K. Roy A. Venkatesh V. Marthandam S. B. Dronavalli Douglas Wells Ronald Rogge 《Journal of Materials Engineering and Performance》2005,14(2):203-211
Transmutation of nuclear waste is currently being considered to transform long-lived isotopes to species with relatively short
half-lives and reduced radioactivity through capture and decay of minor actinides and fission products. This process is intended
for geologic disposal of spent nuclear fuels for shorter durations in the proposed Yucca Mountain repository. The molten lead-bismuth-eutectic
will be used as a target and coolant during transmutation, which will be contained in a subsystem vessel made from materials
such as austenitic (304L) and martensitic (EP-823 and HT-9) stainless steels. The structural materials used in this vessel
will be subjected to welding operations and plastic deformation during fabrication. The resultant residual stresses cannot
be totally eliminated even by stress-relief operations. Destructive and nondestructive techniques have been used to evaluate
residual stresses in the welded and cold-worked specimens. Results indicate that tensile residual stresses were generated
at the fusion line of the welded specimens made from either austenitic or martensitic stainless steel, with reduced stresses
away from this region. The magnitude of residual stress in the cold-worked specimens was enhanced at intermediate cold-reduction
levels, showing tensile residual stresses in the austenitic material while exhibiting compressive stresses in the martensitic
alloys. Comparative analyses of the resultant data obtained by different techniques revealed consistent stress patterns. 相似文献
13.
聚晶金刚石复合片产品内部普遍存在残余应力,这是造成其非正常失效的主要因素。我们详细研究了金刚石复合片内部残余应力的组成,并采用X射线衍射仪建立了聚晶金刚石复合片残余应力的检测方法,研究了聚晶金刚石复合片的残余应力分布规律。利用XRD检测残余应力的方法,分别研究了聚晶金刚石层厚度、金刚石粒度尺寸、两相界面结合形状以及金属Co对复合片的残余应力的影响规律,为控制PDC内部应力提供参考。结果显示:金刚石层表面残余应力最大的压应力在中心位置,从中心到边缘,应力的大小逐渐降低;PCD层与硬质合金基体界面附近的应力值对PDC使用性能的影响最大。 相似文献
14.
对振动时效后的构架进行破坏性疲劳试验,指出检验振动时效后构架尺寸稳定性及疲劳寿命是衡量振动时效工艺好坏的的最重要指标。在国内,第一次用价格昂贵的大型振动时效构架进行破坏性疲劳试验,为构架使用振动时效工艺奠定理论及试验基础。 相似文献
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Based on the Almen method,the authors have modified this test method so that the results of the simple testcan be correlated to the absolute values of residual stress measured fy conventional methods such as X-ray diffraction ormechanical techniques.The technique utilizes changes in the strain of standardized test substrates, which is measured byBHP-700℃ temperature-compensated reststance strain gauges, as an indication of the level of residual stress in thesprayed coatings. Based on the concept that the sprayed coating on the surface of substrate with residual stresses acts aforce (N) and bending momeat (M) on the test piece,the calculating equation of residual stress in the coatings hasbeen proposed. The results of the test method showed that the technique is potentially reliable and accurate, althoughdeficiencies and many controversies are still exist. 相似文献
17.
Chuan Liu Yi Yan Xiaohua Cheng ChunJing Wang Yong Zhao 《Science & Technology of Welding & Joining》2013,18(3):193-199
ABSTRACTA multipass thick welded specimen restrained by three saddle-shape plates welded to the bottom surface was prepared and treated using the post-weld ultrasonic impact treatment (UIT). The stresses in the specimen were measured and analysed. Results show that the as-welded stresses on the top surface of the restrained specimen do not drop quickly beyond the weld zone as compared with the typical welding stress distributions in thick unrestrained specimens. The UIT induces compressive stresses with a depth up to 2–4?mm and it has little effect on the as-welded stresses outside of the UIT-treated region. The welding of restraining plates causes a significant increase of the longitudinal stress within the local welding region. 相似文献
18.
Grinding residual stresses of silicon wafers affect the performance of IC circuits. Based on the wafer rotation ultra-precision grinding ma-chine, the residual stress distribution along grinding marks and ground surface layer depth of the ground wafers are investigated using Raman microspectroscopy. The results show that the ground wafer surfaces mainly present compressive stress. The vicinity of pile-ups between two grinding marks presents higher a compressive stress. The stress value of the rough ground wafer is the least because the material is removed by the brittle fracture mode. The stress of the semi-fine ground wafer is the largest because the wafer surface presents stronger phase trans-formations and elastic-plastic deformation. The stress of the fine ground wafer is between the above two. The strained layer depths for the rough, semi-fine, and fine ground wafers are about 7.6 m, 2.6 m, and 1.1 m, respectively. The main reasons for generation of residual stresses are phase transformations and elastic-plastic deformation. 相似文献
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离子注入与沉积TiN膜层中的残余应力 总被引:1,自引:0,他引:1
利用掠入射X射线衍射(GIAXRD)研究了GCr15轴承钢表面等离子体浸没离子注入与沉积(PⅢ&D)氮化钛(TiN)薄膜后膜层表面的应力状态.用X射线衍射(XRD)分析了处理后膜层的化学组成.探讨了薄膜厚度和掠入射角对表面膜层中应力变化规律的影响.结果表明,表面膜层中主要存在TiN相,同时含有少量的TiO2和钛氮氧的化合物.不同工艺下,TiN/GCr15轴承钢试样表面膜层中存在的应力均为压应力;且应力值随着掠入射角度的增大而减小,随着薄膜厚度的增加而降低. 相似文献