共查询到20条相似文献,搜索用时 625 毫秒
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金属基铸造颗粒复合材料的研究现状及发展 总被引:5,自引:0,他引:5
综述了国内外金属基铸造颗粒复合材料的制取方法和特点;对复合材料凝固过程中粒子的分布情况和改善其分布状态的方法进行了分析;阐述了颗粒与基体界面结合情况,指出,当粒子与基体间存在扩散层或反应层时,二者的结合是牢固的,归纳了颗粒对材料性能的影响,对金属基铸造颗粒复合材料的发展提出了建议。 相似文献
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金属基电子封装复合材料的研究进展 总被引:12,自引:0,他引:12
集成电路和芯片的封装技术的快速发展对封装材料提出了更高的要求。由于传统的金属封装材料不能满足现代封装技术的发展需要,向金属基体内添加低热膨胀系数的陶瓷或其它物质制成金属基电子封装复合材料已成为金属基复合材料今后重点发展的方向之一。本文阐述了金属基体、增强体及其体积分数、制备工艺对复合材料热性能的影响。 相似文献
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采用纸质材料制成三维管状模型,经过纸质模型碳化、反应性渗硅处理获得多孔SiC陶瓷预制体,选择铸造性能好、成形缺陷小的铸铁作为金属基体,采用铸渗法制备了SiC陶瓷增强金属基复合材料,通过XRD,SEM等分析手段研究了多孔SiC陶瓷和复合材料的显微组织和界面结构。研究表明,纸质模型800℃温度碳化,反应性渗硅温度1600℃时制备的多孔SiC陶瓷预制体三维结构稳定,烧结后变形小,微观组织结合紧密;通过铸渗法制备的SiC陶瓷增强金属基复合材料界面结合良好,无明显缺陷。该方法中增强相结构可设计性好,铸渗法制备多孔陶瓷金属基复合材料质量高,为多孔陶瓷增强金属基复合材料的获得提供了试验新方法。 相似文献
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BN/Al金属基复合材料陶瓷增强剂与其金属基体之间的良好结合,是获得金属基复合材料高强度的关键,但是通常由于金属与陶瓷在物理、化学、电学以及力学性能上的差异,而很难获得良好的结合,采用传统的粉末冶金法就得不到性能良好的BN/Al金属基复合材料。近年来... 相似文献
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《International Journal of Cast Metals Research》2013,26(1-4):111-114
AbstractThe filling and remelting of an industrial scale composite casting has been simulated to investigate the effect of fluid flow patterns in the liquid metal on the remelting of the shell material of the composite casting. In the composite casting under investigation, an outer shell material is first cast inside a large cylindrical mould, which is then assembled to additional mould parts, and the core material is poured into the shell/mould assembly. During casting of the core, a thin layer of the shell material re-melts and mixes with the core material producing a bonding layer of intermediate composition. Obtaining the optimum re-melting and thus intermediate bonding zone between the shell and core is critical to producing high quality rolls. The present numerical model employs the volume of fluid method and an enthalpy-porosity technique to couple the filling of the core material and re-melting of the shell material. The interface between the solid and liquid phases is tracked and can be used as a guide to examine the extent of remelting and, to some degree, mixing of the shell and core material. Simulations have shown that the circulation loops that form in the liquid metal pool significantly affect the amount of shell material that remelts. 相似文献
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《International Journal of Cast Metals Research》2013,26(3):138-142
AbstractIn the furan resin moulding technique sulphur in P-toluenesulphonic acid (PTSA), usually used as the hardener, has been identified as an important factor causing graphite degeneration at the metal/mould interface, especially at lower graphite nodularity levels. The greatest surface layer thickness and the lowest graphite nodularity, and shape factors, were obtained with irons solidified in moulds coated with an S bearing material. Uncoated moulds provided better results, but employing a MgO type coating effectively neutralised the sulphur migrating from the mould. In the present solidification conditions, the application of an active mould coating also influenced the graphite phase characteristics in the entire section of the casting, up to its centre. Negative effects were observed using an S bearing coating and positive effects from an MgO based coating. 相似文献
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铝合金铁型覆砂铸造工艺参数研究 总被引:1,自引:0,他引:1
铁型覆砂铸造是在金属型(称为铁型)内腔覆上一薄层型砂而形成铸型的一种新型铸造工艺,其主要工艺参数为铁型壁厚和覆砂层厚度.我们通过不同的覆砂层厚度对铝合金圆柱试样进行铸造,利用热电偶测其凝固冷却曲线,分析了铸造过程中砂型厚度和铁型厚度对冷却速度的影响. 相似文献
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柴油机气缸盖消失模铸造模具CAD/CAM 总被引:4,自引:2,他引:2
详细地介绍了消失模铸造模具CAD/CAM的设计思路和制造工艺流程 ;采用该技术 ,有效地改善了模具的结构 ,明显地缩短产品模具的开发周期 ,成功地完成了柴油机气缸盖消失模模型的生产制作任务 ;实现了消失模铸造模具的国产化。 相似文献
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用颗粒推移模型模拟Al-Si/SiCp复合材料微观组织 总被引:1,自引:1,他引:1
对搅拌铸造法制备SiC颗粒(SiCp)增强Al-7.0%Si(质量分数)复合材料的微观组织形成过程进行了模拟研究,建立了常规凝固条件下相应的宏观传热、等轴枝晶形核生长以及颗粒推移的二维计算模型,采用一种改进的CA(cellular automaton)方法与有限差分法耦合进行数值计算,研究了不同铸造方式对复合材料微观组织以及颗粒分布的影响.为了验证模拟结果,浇注了阶梯形金属型和砂型试样、结果表明,模拟得到的复合材料颗粒分布及微观组织与实验结果吻合良好. 相似文献
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《International Journal of Cast Metals Research》2013,26(4):177-190
AbstractBurn-on and penetration defects in steel casting are principally caused by localised overheating of the sand mould or cores. Such overheating can cause liquid metal to compromise the mould surface and entrain onto the surface of the mould. A method has been developed to predict likely burn-on and penetration defect locations as part of a standard casting simulation. The method relies on determining, from simulation results, the locations where the mould is above a certain critical temperature. The critical temperature is generally above the temperature at which the steel is fully solidified. By measuring the time periods during which these locations in the mould are above the critical temperature, burn-on and penetration defects can be predicted. The method is validated through comparison with previous experimental data. Several parametric studies are conducted to investigate the sensitivity of the predictions to the choice of the critical temperature, the interfacial heat transfer coefficient between the steel and the mould, the pouring temperature, and the mould material. The results of one case study are presented where burn-on or penetration defects observed on a production steel casting are successfully predicted. 相似文献