共查询到19条相似文献,搜索用时 125 毫秒
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介绍了近年来前苏联、美国、中国低温钛合金的研究和应用现状.低温钛合金的应用主要集中在军事工业,民用较少,主要原因在于钛合金的价格比较昂贵.目前国内外对于低温钛合金的研究及应用处于低迷状态,主要应用的是TA7 ELI和TC4 ELI,但它们都有自身无法克服的缺点,因而限制了其应用.我国自主研制的低温钛合金尚缺乏完善的合金性能测试及数据积累.今后还需要对综合性能更为优异的新型低温钛合金如CT20等进行深入的研究、完善,并予以推广. 相似文献
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随着对深空领域的进一步探索,氢氧发动机以其大推力、高稳定性、无污染等优点受到了越来越多的重视。低温钛合金作为氢氧发动机低温结构的重要材料,直接影响着氢氧发动机的综合性能。以TA7ELI,TC4ELI,CT20为重点对象,详细介绍了低温钛合金的发展历史及研究现状,对目前各国广泛应用的低温钛合金性能进行了综合对比,同时介绍了低温钛合金在不同温度下的变形机理及失效形式。此外,对低温钛合金的主要成形工艺进行了详细论述。最后,基于以上介绍,提出低温钛合金未来应该朝着更高性能、更低成本以及开发新型成形工艺3个方向发展。 相似文献
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我国材料工作者对不同领域使用的钛合金进行了卓有成效的研究工作.经过近50年的发展,我国的钛工业在科技和生产上都取得了长足进步.概述了我国自主研发的各种钛及钛合材料,包括高温钛合金、高强钛合金、低温钛合金、耐蚀钛合金、船用钛合金、医用钛合金等.最后对我国钛工业进行了简要的展望. 相似文献
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目的 研究不同Co含量电沉积Ni-Co纳米镀层的热稳定性能及其扩散连接应用效果。方法 在TC4钛合金表面电沉积Ni-Co镀层,改变镀液中Co含量(0、5、20g/L),利用金相显微镜(OA)和透射电镜(TEM)观察分析镀层800℃热处理前后的微观组织。在真空扩散设备中进行TC4钛合金低温扩散连接(800℃、1 h),利用万能拉伸机检测扩散连接接头的剪切性能。结果 添加Co元素不仅能够减小镀层晶粒至19.2 nm,还能够提高其热稳定性能。纯镍镀层在800℃热处理5 h后晶粒长大至17.2μm,而Ni-20 g/L Co镀层晶粒在相同条件下仅长大到10.5μm且生长初期并未发现异常长大晶粒。以2.5μm厚的Ni-Co镀层为中间层进行TC4钛合金低温扩散连接,接头剪切强度高达543.4 MPa。结论 Co元素的添加降低了晶界能量,提高了Ni-Co镀层的热稳定性能;作为TC4钛合金扩散连接的中间层,提高了原子的扩散系数,实现了TC4钛合金低温扩散连接,对工程应用具有重要意义。 相似文献
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空间低温制冷技术的应用与发展 总被引:1,自引:0,他引:1
随着空间技术的快速发展,空间低温制冷技术也取得了长足的进步。介绍了国内外空间低温制冷技术最新研究进展及其在对地遥感和深空探测航天器中应用情况,结合国内空间低温制冷技术的发展现状,提出了我国开展空间制冷技术研究的几点建议。 相似文献
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钛合金以其优异的生物相容性、出色的力学性能和抗腐蚀性而广泛应用于航空航天等领域。然而,现代工艺制备的钛合金存在延展性和耐疲劳性较差的问题,同时钛金属本身的耐磨性也较差,因此需要通过合适的后处理工艺来改善其力学性能。在这种背景下,深冷处理凭借其便捷、无污染、低成本及能显著改善金属材料组织和综合性能等优势,成为机械加工领域备受瞩目的研究方向。首先简要介绍了深冷处理的发展历程以及2种主要加工方法:液态法和气态法,同时概括了气态法的具体流程。其次重点综述了国内外深冷处理工艺对钛合金组织和织构的影响,分别从深冷时间、深冷温度与循环次数3个方面,归纳了深冷处理工艺对钛合金硬度和拉伸性能的影响以及深冷工艺的作用机理,并进一步探究了深冷处理工艺对钛合金制件摩擦磨损性能和耐疲劳性能的影响规律。最后介绍了深冷处理复合工艺方法,为基于深冷处理的加工工艺的发展提供有益参考和启示。 相似文献
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铝合金的深冷处理工艺主要有快冷、慢冷及循环处理三种。深冷处理后,铝合金的组织和性能通常得到改善,改善程度与合金成分及深冷工艺有关。铝合金的深冷强化机制有别于黑色金属及其合金;目前有位错、亚晶、晶粒转动等理论假说。 相似文献
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Tool wear in cryogenic turning of Ti-6Al-4V alloy 总被引:1,自引:0,他引:1
Though titanium alloys are being increasingly sought in a wide variety of engineering and biomedical applications, their manufacturability, especially machining and grinding imposes lot of constraints. Rapid tool wear encountered in machining of titanium alloys is a challenge that needs to be overcome. Cryogenic machining with liquid nitrogen as coolant is being investigated by researchers to reduce the cutting zone temperatures and enhance the tool life. The effects of cryogenic cooling have been studied on growth and nature tool wear in the present investigation while turning Ti-6Al-4V alloy bars with microcrystalline uncoated carbide inserts under dry, wet and cryogenic cooling environments in the cutting velocity range of 70-100 m/min. Cryogenic cooling by liquid nitrogen jets enabled substantial improvement in tool life through reduction in adhesion-dissolution-diffusion tool wear through control of machining temperature desirably at the cutting zone. 相似文献
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Titanium alloy with a low density, high specific strength, corrosion resistance and good process performance, is the ideal structural materials for the aerospace engineering. Based on the microstructure of titanium alloys, it can be divided into α-type titanium alloys (heat-resistant titanium alloys), β-type titanium alloys and α + β-type titanium alloys. The research scopes also include the fabrication technology of titanium alloys, powder metallurgy, rapid solidification technology, and other military and civilian applications of titanium alloys. Titanium and its alloys have become the ideal structural materials used for the fuselage, and accounted for a significant part of the structural quality in most military aircrafts. Titanium’s future market expectations need to be considered in the macro level market. Apart from the supply and demand trends of titanium market, it is necessary to consider the impact of technological innovations that can help to reduce the cost of titanium production. 相似文献
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未知系统周期激励源分离方法的有效性分析 总被引:1,自引:1,他引:0
建立了履带式挖掘机的11自由度简化力学模型,利用拉格朗日法完成了数学建模。确定了挖掘机越障过程中所受到的激励,求解了系统在不同激励输入形式下的动态响应。结合虚拟样机技术,完成了履带式挖掘机在只有路面障碍激励下的虚拟样机动力学仿真,将简化力学模型数值求解结果与虚拟样机动力学仿真结果相互对比。结果表明:两种分析方法得到的动力学响应结果均符合预期分析;两种方法分析结果基本吻合,实现了两种模型的相互校验,说明了所提出的动力学建模与分析方法的正确性,可为履带式挖掘机越障动态特性研究提供借鉴与参考。 相似文献
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T. Vignesh Kumar Rama Thirumurugan B. Viswanath 《Materials and Manufacturing Processes》2017,32(16):1789-1805
The research area “Cryogenic Treatment of Materials” has been the subject of a multitude of research studies and therefore needs a proper review article to highlight the present state of understanding and to define the future research direction. Though reviews on cryogenic processing of tool steels are available, there has not been a review that attempts to systematically discourse the effect of cryogenic treatment on the metallurgy of various ferrous alloys. While previous reviews address transformation of retained austenite and the formation of fine precipitated carbides as the major phenomena of cryogenic treatment, developments such as the refinement of pearlite matrix, formation of fine martensite, and enhancement of properties in low carbon steel and cast iron are discussed in detail in this article. In addition, the influence of individual treatment parameters, their sequence, and the effect of room temperature stabilization on the metallurgical changes are extensively addressed. Moreover, many of the contradicting observations/conclusions such as detwinning of martensite and dissolution of secondary carbides during cryogenic treatment are highlighted for further clarification. Finally, applicability of cryogenic treatment for a range of ferrous alloys is presented with an emphasis on scope for future research. 相似文献