苯胺类缓蚀剂的量子化学研究

用量子化学半经验计算方法CNDO/2程序,研究了苯胺类缓蚀剂的电子性质与缓蚀性能的关系。结果表明质子化的胺基是苯胺衍生物与金属作用的活性部位。提出了该类分子作为酸性介质中金属缓蚀剂在铁表面形成吸附膜的作用机理。     

Experimental and numerical life prediction of thermally cycled thermal barrier coatings

This article addresses the predominant degradation modes and life prediction of a plasma-sprayed thermal barrier coating (TBC). The studied TBC system consists of an air-plasma-sprayed bond coat and an air-plasma-sprayed, yttria partially stabilized zirconia top layer on a conventional Hastelloy X substrate. Thermal shock tests of as-sprayed TBC and pre-oxidized TBC specimens were conducted under different burner flame conditions at Volvo Aero Corporation (Trollhättan, Sweden). Finite element models were used to simulate the thermal shock tests. Transient temperature distributions and thermal mismatch stresses in different layers of the coatings during thermal cycling were calculated. The roughness of the interface between the ceramic top coat and the bond coat was modeled through an ideally sinusoidal wavy surface. Bond coat oxidation was simulated through adding an aluminum oxide layer between the ceramic top coat and the bond coat. The calculated stresses indicated that interfacial delamination cracks, initiated in the ceramic top coat at the peak of the asperity of the interface, together with surface cracking, are the main reasons for coating failure. A phenomenological life prediction model for the coating was proposed. This model is accurate within a factor of 3.     

INFLUENCE OF RESIDUAL STRESS AND SURFACE MORPHOLOGY ON FATIGUE PROPERTIES OF STEEL 60Mn

Influence of residual stress and surface morphology induced by shot-peening on fatigue behav-ior of a medium temperature tempered spring steel 60 Mn has been studied.The compressiveresidual stress induced in the near-surface region may improve fatigue limit from 930 to 1010MPa,and the very high tensile residual stress in the interior may reduce it from 1010 to 940MPa,whereas the severe surface damage may cause a drop-off of it from 1010 down to 800MPa.Fatigue cracks initiated in such position where the equivalent Mises stress,includingresidual stress,exceeded the local strength of the material.The compressive residual stress,induced by shot-peening,may intensify the effect of crack closure,so as to decrease the crackgrowth rate.     

椭圆形弯曲件的回弹控制

分析了椭圆形弯曲件产生回弹的原因,阐述了减少弯曲回弹的措施,并通过计算设计出了相应的弯曲模结构,此模具结构生产出了合格零件,可为类似零件的成形提供参考。     

Effects of distance between arc and heat sink on stress and distortion in DC-LSND welding technology

The characteristics of temperatures, stresses and strains fields have been studied numerically for a titanium alloy sheet welded with an improved gas tungsten arc welding method, in which a trailing spot heat sink is introduced to control the welding stress and distortion. The impinging jet model is employed to describe the internee heat transfer between the cooling media and the top suufuce of the workpiece. The influcnee of the distance between arc and heat sink is investigated. Results show that there is an ideal range of distance. Using the ideal distance, a low stress and no distortion welding structure can be derived.     

对接焊缝残余应力的有限元分析

采用有限元方法数值模拟了对接焊缝残余应力大小和分布，计算结果与试验结果基本吻合，证明有限元方法是一种经济而有效地预测焊接接头残余应力的方法，可以为制定正确的焊接工艺，改善接头性能提供理论依据。     

BEHAVIOUR AND MECHANISM OF STRESS CORROSION CRACKING FOR Al-Li-Cu-Mg ALLOY

Studies were made of the influence of aging conditions and applied potentials on thestress corrosion carcking(SCC)susceptibility for an Al-Li-Cu-Mg alloy by slow strainrate technique.The relationship between the relative hydrogen content on specimensurface,the applied potentials and elapsed time has also been examined.The SCCsusceptibility was found to be dependent on aging conditions in which the peak agedcondition gave the worst SCC resistance and the natural aged condition had the best one.The SCC susceptibility and surface hydrogen content relates to the applied potentials.The anodic potentials increase SCC susceptibility,while the cathodic ones below thecritical potential accelerate SCC.It is considered that both the anodic dissolution and     

基于XRD的薄膜界面结合强度试验研究

利用X射线衍射技术（XRD）分析了薄膜结合界面应力及其变化规律，通过对薄膜界面结合状态的检测，建立了X衍射法测量薄膜界面结合强度的原理、方法与过程。其检测界面结合强度方法可对薄膜试样进行非接触检测，适用于晶体或多晶体薄膜的界面结合强度测量，是一种研究无损检测薄膜结合强度的试验新方法。     

汽车半轴多楔楔横轧成形应力变化规律分析

本文根据楔横轧多楔轧制特点,建立了楔横轧多楔轧制半轴细杆部的三维有限元模型,编制了半轴细杆部多楔轧制过程进行有限元模拟的命令流程序,详细的分析了轧制过程中楔入段、展宽段主楔在侧楔作用下轧件内部应力变化规律,为多楔轧制半轴的模具设计和工艺参数的确定提供理论依据.     

焊接过程三维应力变形数值模拟研究进展

焊接非平衡加热、冷却过程导致产生焊接应力与变形，严重影响焊接过程及结构的服役行为，是焊接结构生产制造过程中必须解决的关键技术问题之一。作者对目前国内外焊接过程中焊接应力与变形的数值模拟研究及工程应用进行了分析。结合研究小组的研究工作，对大型复杂结构焊接过程中三维焊接应力变形数值模拟存在的困难、需要解决的主要技术问题进行了评述，并介绍了几个工程应用实例。