共查询到19条相似文献,搜索用时 125 毫秒
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采用喷射成形工艺制取超高碳钢,并对其超塑性及热加工后的综合性能进行了研究。研究结果表明,喷射成形超高碳钢不仅具有优良的显微组织,而且还有独特的超塑性,在热加工后其综合性能得到明显提高。 相似文献
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结构材料喷射成形技术与雾化沉积高温合金 总被引:3,自引:0,他引:3
喷射成形是利用快速凝固方法直接制备金属材料坯料或半成品的先进材料制造技术 ,喷射沉积高温结构材料的冶金性能好、生产效率高、成本低 ,因而在近几年得到了迅速发展 .本项研究的主要目的是要通过喷射成形工艺参数的调整、最大限度地直接减少喷射成形坯中的孔隙度 ,进而得到优质坯料 .利用优化的雾化喷射沉积技术制备了多种高温合金沉积坯 ,沉积坯整体致密、晶粒细小、组织均匀、无宏观偏析、含气量低、力学性能提高 .还简要地比较了喷射成形高温合金与用常规铸锭冶金工艺和粉末冶金工艺制备高温合金的异同 ;总结了航空材料研究院喷射成形高温材料近年来的研究状况 ,包括专用高温材料喷射成形装置和技术及其应用 . 相似文献
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以Ti粉、B4C粉、石墨和蔗糖(C的前驱体)为原料,采用机械粘结法制备了Ti-B4C-C系复合粉,采用前驱体法制备了Ti-B4C-C-蔗糖系复合粉,并分别利用两种复合粉进行自反应喷射成形试验,获得了Ti(C,N)-TiB2复合陶瓷坯件。通过XRD、SEM等方法观察了复合粉与喷射沉积坯件的组织结构,分析了其相组成,并测试了成形坯件的孔隙率及断裂韧性等力学性能,对比分析了复合粉制备工艺对喷射成形材料组织结构及性能的影响。研究结果表明:与机械粘结法制备的,Ti-B4C-C系复合粉相比,采用前驱体法制备的Ti-B4C-蔗糖系复合粉内部粘结强度稍低,但粉体内部混合更均匀,各组元间接触更充分,因而自反应喷射成形过程中的SHS反应更加充分。二者喷射成形所得材料均以Ti(C,N)-TiB2主相、部分钛的氧化物为副产物相,并有一定孔隙。但Ti-B4C-蔗糖系复合粉喷射沉积坯件副产物相少,组织均匀致密,且材料的断裂韧性高,综合性能明显优于Ti-B4C-C系复合粉喷射沉积坯件。 相似文献
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SHI Haisheng WU Xingfang ZHANG Jingguo 《材料导报》2004,18(Z3):163-165
报道了首次采用喷射成型工艺制取超高碳钢,并研究了其超塑性及变形后的显微组织.研究结果表明:喷射成型超高碳钢不仅具有优良的显微组织,而且还有独特的超塑性;在高温超塑拉伸应力作用下,超高碳钢变形后的显微组织存在明显的不均匀性. 相似文献
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采用喷射成形技术制备了Al95Cu2Fe1Ni1Ce0.5Zr0.5合金材料,研究了该合金快速凝固组织的形成机制,并以沉积态及热挤压态材料的拉伸性能进行了测试,结果表明:喷射成形快速凝固技术显著地细化了合金组织,预成菜毛坯组织的微观不均匀使沉积态材料的综合力学性能降低,热挤压工艺可改善合金的均匀性,提高材料性能。 相似文献
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喷射轧制加工技术是一种金属半固态近净成形新技术。与铸轧、喷射沉积、铸锭冶金制备的材料相比,喷射轧制材料具有均匀细晶组织和优异综合性能。综述了近年来喷射轧制技术的理论研究,以及数值模拟等方面的研究进展。针对喷射轧制理论研究方面存在不够深入的问题,提出了借鉴喷射成形和双辊铸轧较为成熟的理论。采用实验研究和数值模拟相结合的方法,研究工艺参数对喷射轧制过程中液滴的动力学行为和热力学行为的影响,以及对材料的显微组织和力学性能的影响,探索喷射轧制的基本规律。最终预测了该技术能为金属加工业提供一种节能节材、短流程的板带材生产新途径的发展前景,对该技术及其过程原理的深入研究将形成金属半固态近终形加工的新理论。 相似文献
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Characteristic Features and Specific Qualifications of the Sprayforming Process to be Generalized The solidification and cooling process of spray formed materials predominates the extent of any segregation and separation process, which is conducive to avoid macro‐segregation and to diminish concentration of alloying components at the grain boundaries. The risk of coarse porosity or of hot cracking is reduced significantly by the momentum of the mass flow during spray deposition. This means that those materials which e.g. during the casting process tend to establish strong segregation effects and cavities and/or hot cracks as well as those which tend to create filaments of carbides, nitrides or sulphides during rolling can be generated by the spray forming process in large dimensions with chemical homogeneity and without any of those defects. A characteristic feature of spray formed materials is the fine equiaxed grain structure and the high ductility. Specific features of this new free forming process will be discussed. 相似文献
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The economy of the spray forming process is restricted by the generation of overspray, which in many cases cannot be re‐introduced into the process by re‐melting or co‐injection. Especially for small deposits, such as small diameter tubes (diameter <100 mm), the amount of overspray can become large in conventional spray‐forming processes. In this work, an alternative process with a pressure‐gas‐atomizer operating at low melt flows is presented. Tubes with diameters of 50 mm and 90 mm were spray‐formed and analyzed regarding yield and porosity. It was found that yields up to 96% can be achieved with porosities below 1% if proper process parameters are identified and used. An evaluation of the yield and the corresponding achievable porosity is conducted to identify resource‐efficient sets of parameters. 相似文献
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热等静压对喷射成形TiAl基合金孔隙率的影响 总被引:3,自引:0,他引:3
着重研究了气体辅助喷射成形和离心喷射沉积形成的Ti-48Al-2Mn-2Nb金属间化合物的孔隙率以及热等静压工艺对合金孔隙率的影响,利用Quantimet图象分析仪定量测试了各种状态样品的孔隙率。结果表明,气体雾化成形合金的孔隙率约3.29%,离心喷射盛开有合金的孔隙率约2.20%,孔隙率的大小与喷射成形工艺密切相关。 相似文献
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Huifen PENG Baoqi WANG Jianjun ZHANG Xiaoyan SONG Xiaoli MA Nanju GUSchool of Materials Science & Engineering Hebei University of Techonology Tianjin China 《材料科学技术学报》2004,20(5):567-570
In this research, we tried to find a simple processing method to break up the network carbides in ultrahigh carbon steels (UHCS). Our results revealed that Al addition was favorable to the decrease in the proeutectoid carbides, the pearlite-colony size and the pearlitic interlamellar spacing of the forged microstructures, and that a fully-pearlitic structure was obtained in the UHCS containing 1.6 wt pct Al. The quenching-and-tempering process resulted in fine microstructure in those steels. On the other hand, the strength of the UHCSs increased with the increase of the Al content, and the highest strength was obtained at the UHCS with 1.6 wt pct Al. The UHCSs with Al contents higher than 1.3 wt pct showed a high tensile strength of more than δb=1000 MPa and good ductility of higher than δ5=10% at ambient temperature. 相似文献