Modeling of Intercritical Heat Treatment of DP and TRIP Steels

The final microstructure of DP and TRIP assisted steels can evolve after hot working (hot rolling) or during post heat treatment process. In the formation of the final structure a number of different technological parameters have important roles, e.g. end temperature of rolling, cooling rates, temperature of intercritical annealing, etc. As a result of the individual factors and their combinations a lot of product technology routes are feasible. The effect of the different combinations of these technological parameters on the microstructure can be mapped by the special Jominy end-quench test (so called intercritical Jominy end-quench test) described in this paper. Unlike the traditional Jominy test, in this case there is a partial anstenizing between A1 and A3 temperatures which results in a given amount of ferrite in the microstructure before quenching. The method developed can be applied for mapping DP and TRIP assisted steels' microstructure in a wide range of technological parameters. The analysis of measured and calculated data can help us find the technological parameters optimal from the microstructural point of view.     

Ti9Al合金的氢塑性效应

采用真空自耗电弧炉熔炼制备Ti9Al合金，通过渗氢处理显著提高氢含量，在凸轮塑性试验机ЧПИ-2上以10mm／min的速度进行热模拟试验。研究发现：氢可以降低Ti9Al合金的相变温度，扩大α β区的温度范围；氢作为卢稳定剂会妨碍或完全抑制以Ti3Al为基的α2相的析出；钛合金的氢合金化可促使卢相在更低温度下稳定化，明显地提高了Ti9Al合金塑性。     

铜塔铸造工艺

介绍了五台山铜塔铸造工艺,由于其结构特殊,故采用了3种工艺分别铸造而成:细砂湿模造型、树脂砂毁模贴皮造型和熔模铸造.介绍了铜塔表面化学着色技术.铜塔铸造工艺对其他相似艺术铸品具有一定的借鉴价值.     

Effects of CeF3 on properties of self-shielded flux cored wire

0 IntroductionSelf-shielded flux cored wire is a newly developedwelding material used without gas protection. Use of suchcored wires has grown rapidly in developed countriesbecause of the following advantages: simple use, goodwind resistance ability, lower cost resulted from highproductivity and strong desulfurization ability[1]. Self-shielded flux cored wires are preferred for on-site weldingsuch as ship and barge building, storage tank, bridge,offshore oil platform buildings and so on[2 -3].…     

超细纤维素胶体和丙烯酰胺的接枝共聚

本文用纤维素材料经酸分解制备具有平衡聚合度（LODP）的微晶纤维素，再分散成超细纤维素胶体（准均相纤维素体系）。用扫描电镜（SEM）观察处理前后的纤维素颗粒尺寸，并比较它们和丙烯酰胺接枝共聚的反应速率、聚合转化率、接枝率、接技效率、聚丙烯酰胺支链的分子量及其分布的情况。     

Study of stability of high‐temperature polyimides using TG/MS technique

The oxidative stability of the carbon fiber‐reinforced composite of polyimide was examined, in real time, using the evolved gas analysis techniques. Off‐gas degradation products suggested the onset temperature for chain scissions to be fairly low at about 190–220°C. Based on the off‐gas products present and the trend of their release, the composite degradation mechanism appeared to be similar between 190 and 371°C, thereby marking 371°C to be the highest accelerated aging temperature for its long‐term lifetime prediction. Beyond 371°C, different degradation mechanisms would apply. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1219–1227, 2002     

Elastic Properties and Microcracking Behavior of Particulate Titanium Diboride–Silicon Carbide Composites

The spontaneous microcracking of particulate TiB₂–SiC composites is studied as a function of TiB₂ volume fraction. The degree of microcracking was examined by measuring elastic properties from room temperature to 1300°C. The results showed that only one composition contains microcracks. All other compositions did not microcrack regardless of TiB₂ volume fraction. This was attributed to the difference in the sintering aids. In particular, the Al₂O₃ sintering aid needed in these compositions had reacted with SiO₂ to form an amorphous grain boundary phase that allowed residual stresses to relax by viscous flow at moderate to high temperatures. The existence of this amorphous grain boundary phase was directly observed by transmission electron microscopy.     

Preparation and characterization of porous carbon beads and their application in dispersing small metal crystallites

Porous carbon beads were prepared by the pyrolysis of poly(vinylidene chloride) beads that were synthesized by suspension polymerization. After prolysis treatment at 180–300 °C under argon stream, the polymeric beads were further carbonized at 1000 °C for 3 h under argon stream to acquire porous carbon beads, of which the specific surface area was about 1000 m²/g, and pore size was mainly in the width range of 0.8–1.2 nm. The carbon structure and surface chemical composition characterized by X-ray diffraction and X-ray photoelectron spectroscopy, depended on the preparation temperature and the relations between them were examined. The characterization of the carbon beads by scanning electron microscopy, atomic force microscopy presented the morphological structure of the carbon beads surface and a global view of pores. The dispersion of nickel crystallites on the carbon beads surface was characterized by electron microprobe analysis. This study reveals that uniform surface morphological structure leads to the fine dispersion of metal crystallites.     

Effect of miscibility and forced compatibility on damping properties of CIIR/PAc blend

In this study, a kind of novel damping materials was prepared based on the blend of chlorinated butyl rubber (CIIR) and polyacrylate (PAc) synthesized by different molar ratio of butyl methacrylate and ethyl acrylate. Research results from experiments and analyses by employing DMA, TEM, and FTIR show that whether at a cocured system or noncocured system, it can be achieved to shift a loss peak of CIIR towards a higher temperature region and to keep the damping value from markedlly decreasing, which broadens the effective damping function area of CIIR to the vicinity of ambient temperature. In the former system, the thermodynamical miscibility of CIIR and PAc, to some extent, is predominated by the molecular design of PAc, while in the latter system, covulcanized networks play a more significant role in improving compatibility and abating the peak split, though the suppression effect of thermal stress on the transition of CIIR T_ll transition still can not be neglected. Furthermore, transition state derived from the cocuring CIIR and PAc cannot make the phase separation completely take place, and consequently results in the deformation of phase morphology of the cocured CIIR/PAc blend. It is the influence of thermodynamics miscibility and forced compatibility in different size that makes the suppression effect of foreign PAc on CIIR T_ll transition be controllable. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3127–3133, 2006     

梭式窑火焰数字图像的边缘检测初探

本文介绍了几种典型的边缘检测算法,对它们各自的特点进行了比较。对梭式窑内的一幅原始图像,可用边缘检测算法提取火焰图像的边缘。