CHARACTERISTICS OF INTERNAL FRICTION AND MODULUS ASSOCIATED WITH NON-EQUILIBRIUM DIFFUSION-TYPE PHASE TRANSFORMATION IN EUTECTOID Al-Zn ALLOY

The characteristics of the low frequency internal friction and the modulus effect associatedwith the non-equilibrium spinodal pretransformation and the following discontinuous trans-formation was investigated in an as-quenched eutectiod Al-Zn alloy.It was observed that theloss of the stability in the lattice,which corresponded to the large-amplitude long-wavelengthstatic concentration wave in the non-equilibrium spinodal pretransformation,did not induceany effect of localized soft modulus.Although there are two aging internal friction peaks inphase transformation which correspond to the appearance and disappearance of the coherencyin spinodal pretransformation and the maximum of the interface area in the discontinuoustransformation respectively,the effect of localized soft modulus did not take place yet.     

压入深度与膜厚对薄膜与基体复合硬度及弹性模量的影响

根据高华建的复合弹性模量模型，提出了用一个测点的载荷-位移曲线计算整个压入深度内薄膜和基体复合硬度分布的方法，探讨了压入深度与膜厚对硬度与弹性模量测量值的影响，指出可由膜-基复合性能反推膜本身的性能。     

熔模铸造型壳抗弯弹性模量的研究

依据材料力学、陶瓷材料的有关理论和方法,分别对水玻璃型壳、硅溶胶型壳及其复合型壳在不同温度时的抗弯弹性模量进行了测试研究.结果表明,耐火材料、温度对型壳的弹性模量有较大的影响,硅溶胶型壳和复合型壳的弹性模量值比水玻璃型壳的大.     

Effect of cold spray deposition of a titanium coating on fatigue behavior of a titanium alloy

The deposition of titanium on a titanium alloy substrate is being examined for potential use as a surface treatment for medical prostheses. A Ti6Al4V alloy was coated with pure titanium by cold gas dynamic spraying. Coatings were deposited onto samples with two different surface preparation methods (as-received and grit-blasted). The fatigue life of the as-received and grit-blasted materials, both before and after coating, was measured with a rotating-bend fatigue rig. A 15% reduction in fatigue endurance limit was observed after application of the coating to the as-received substrate, but no significant reduction was observed on its application to the grit-blasted substrate. The reduction in fatigue endurance limit has been related to the substrate-coating interface properties, the elastic modulus, and the residual stress states. This article was originally published inBuilding on 100 Years of Success, Proceedings of the 2006 International Thermal Spray Conference, (Seattle, WA), May 15–18, 2006, B.R. Marple, M.M. Hyland, Y.-Ch. Lau, R.S. Lima, and J. Voyer, Ed., ASM International, Materials Park, 2006.     

钢球纵轧成形后滑的研究

基于钢球坯纵轧成形工艺,应用弹塑性有限元法,建立了钢球坯连轧成形的实体模型;模拟了轧件在成形过程中的速度场;通过实验研究了后滑的存在及其影响因素。     

在纳米压入仪上进行悬臂梁法测量弹性模量的影响因素分析

对在纳米压入仪上进行悬臂梁法测量弹性模量的主要影响因素进行了综合分析,主要包括加载系统悬置弹簧刚度、压头压入、梁沿截面宽度方向挠曲、梁支座附加挠曲等影响。在考虑这些因素的基础上,得到了悬臂梁的有效挠度,利用有效挠度与载荷之间的关系,评价悬臂梁材料的弹性模量。对单晶硅(100)悬臂梁试样进行了实验,得到其弹性模量为155GPa±9.5%GPa,与参考文献值符合较好。表明在纳米压入仪上进行悬臂梁法测量,只有综合这些影响因素后,才能获得有效、准确的弹性模量测量结果。     

Some new operational modes and parameters of stress relaxation for the viscoelastic characterization of solid polymers. III. The area ratio mode and the intrinsic “strain–clock” function

The introduced area ratio mode of operation with its corresponding parameters seems to have a fairly high sensitivity to the viscoelastic response of the solid polymer. This appeared from the fact that a good distinction among the linear viscoelastic, the nonlinear viscoelastic, and the viscoplastic ranges of behavior can be made. By using a relevant rheological modeling and its corresponding algorithmical approach, in the case of isotactic polypropylene, this material can be characterized as a morphological three‐phase material consisting of an intraspherulitic crystalline, an amorphous phase, and a interspherulitic para‐crystalline phase. In this sense, the material was simulated using two models: the Poynting–Thomson and the Maxwell–Wierchert, from where a good response of the material to the first model appeared. The so‐called intrinsic “strain–clock” function and its corresponding coefficient of strength of nonlinear viscoelastic behavior, which were relieved by the experimental data, seem to be some powerful and very practical “tools” that can give a proven suplementary characterization of the material. Finally, by this intrinsic function, the existence of permanent internal stresses, was confirmed, in an indirect way, which was mentioned in part II of this study. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 149–158, 2003     

Adhesion Mechanisms of Polyurethanes to Glass Surfaces I. Structure-Property Relationships in Polyurethanes and Their Effects on Adhesion to Glass

Polyurethanes were prepared from toluene diisocyanate (TDI), 1-4-butane diol (BDO) and polycaprolactone-based triols with varying molecular weights. Among each molecular weight triol-based urethane, hard segment content was varied from 20% to 70%. Differential scanning calorimetry, tensile testing, and Iosipescu shear testing were done on all the various urethanes prepared. Thermal characterization data revealed the dependence of phase separation on hard segment content as well as on the triol molecular weight. Tensile data and Iosipescu shear data further confirmed the observations made from the DSC data. The data further indicated that phase separation can greatly improve the modulus of cross-linked segmented urethanes. Adhesion of these urethanes to glass surface was evaluated using soda-lime float glass plate. Urethane samples were cast on the air side of the glass plates and adhesion was measured in shear mode. Adhesion data indicated that in addition to hard segment content, modulus, cross-link density, and molecular weight of the triols, phase separation seems to be a major factor in controlling adhesion. Surfaces of the failed adhesion samples were also analyzed and the failure mode was found to be cohesive, in varying degree, with the different urethane systems.     

界面扩展粘度的测量

介绍了界面扩展粘度κ的测定方法及其原理 ,列出了其相应的测定结果 ,同时对各种测定方法进行了分析与比较 ,并对它们的优缺点进行了讨论     

环氧-聚酰胺体系中增韧剂的研究

在环氧-聚酰胺体系中分别加入“海岛结构”QS-1、聚硫橡胶、液体丁腈橡胶增韧改性,通过对固化物剪切强度、弯曲弹性模量及断裂强度的对比,“海岛结构”QS-1增韧综合性能较好.