共查询到19条相似文献,搜索用时 125 毫秒
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含铜铁基粉末冶金材料在烧结前后易发生尺寸变化,为此类零件的生产带来不便。本文介绍了有关含铜铁基粉末冶金材料的烧结过程、烧结过程中铁铜粉末颗粒尺寸变化和烧结尺寸变化的相关研究进展,主要包括以下内容:高于Cu熔点温度烧结时,Cu颗粒熔化扩散渗入Fe颗粒中,在Cu颗粒原本位置形成流出孔隙,从而造成烧结坯尺寸的膨胀;随着烧结温度或烧结时间的增加,烧结过程中铁铜粉末颗粒的尺寸呈增大趋势;影响含铜铁基粉末冶金材料烧结尺寸变化率的主要因素是粉末粒度及合金元素的成分和含量。 相似文献
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粉末冶金铁基结构材料及其零件是粉末冶金中量大面广的产品。粉末冶金结构材料在机械、汽车、仪表等工业中进一步扩大应用,其中重要的问题是必须提高材料的强度。目前我国粉末冶金铁基结构材料(JB2797—81)标准规定,抗拉强度最高为55公斤力/毫米~2(烧 相似文献
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烧结气氛对粉末冶金铁基材料的性能和质量有很大的影响。但由于原料、技术和经济方面的原因,烧结气氛问题在国内一直未得到满意的解决。目前,使用的木炭发生炉煤气、城市煤气转化气、氨分解气等三种保护气氛,很难烧结出质量稳定的中高强度烧结零件。北京粉末冶金研究所成功地把氮基气氛用作粉末冶金铁基材料的烧结保护气氛,使粉末冶金铁基结构 相似文献
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铁基粉末冶金结构零件以其独特的优点和巨大的竞争力已在汽车等行业获得广泛的应用.材料疲劳性能的研究目前仍然是应用和科学研究中的一个重要领域.综述了近年来国内外铁基粉末冶金材料的疲劳与失效行为的研究成果,包括成分、组织和制备工艺等因素对铁基粉末冶金材料的疲劳性能、疲劳裂纹萌生与扩展机制的影响,以及铁基粉末冶金材料的疲劳裂纹扩展速率等方面的研究成果.指出了加强国内相关领域研究,有利于促进粉末冶金学科发展和提升国内的粉末冶金技术水平,对拓展铁基粉末冶金零件的应用具有重要的现实意义. 相似文献
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L. V. Tokova A. A. Zaitsev V. V. Kurbatkina E. A. Levashov D. A. Sidorenko V. A. Andreev 《Russian Journal of Non-Ferrous Metals》2014,55(2):186-190
The features of influence of ZrO2 and WC nanoparticles on the properties of the iron-based metal matrix composite are investigated. The influence of nanoparticles on the compactibility of the powder material and mechanical and tribological properties of alloy is analyzed. It is revealed that the metal matrix composite particle reinforced with nanoparticles, which was fabricated by hot compression technology, is characterized by increased hardness and wear resistance. 相似文献
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分别采用超音速火焰喷涂工艺和爆炸喷涂工艺,在Q235不锈钢基体上制备Fe基非晶合金涂层,对比研究这2种非晶合金涂层在室温下的干摩擦磨损特性,并探讨摩擦磨损机理.结果表明,与超音速火焰喷涂工艺制备的Fe基非晶合金涂层相比,采用爆炸喷涂工艺制备的涂层更致密,孔隙率为2.1%,显微硬度更高,平均硬度高达1 095.6 HV,且耐磨性更好;并且涂层摩擦因数增至稳定值的时间较短,具有更稳定的摩擦磨损行为.超音速火焰喷涂涂层的磨损形式主要以疲劳磨损为主,而爆炸喷涂涂层的磨损形式为粘着磨损和磨粒磨损的综合作用,并以粘着磨损为主. 相似文献
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采用机械球磨和热等静压(hot isostatic press,HIP)相结合的方法制备NbC颗粒增强45CrMoV弹簧钢基复合材料(NbCp/45CrMoV),观察该材料的显微组织、增强颗粒分布和界面结合情况,检测其相对密度、硬度、拉伸性能和摩擦磨损性能,并探讨其断裂行为和磨损机理。结果表明,NbCp/45CrMoV复合材料的组织均匀细小,NbC颗粒均匀地弥散分布在基体之中,且与基体界面结合良好,相对密度达到99%以上。与45CrMoV弹簧钢相比,该材料的硬度和弹性模量增大,分别为44 HRC和208 GPa,抗拉强度略有降低,为1 250 MPa;伸长率由11%减小到2%;耐磨性能大幅提高,特别是在高载荷下,例如700 N时,质量磨损只有HIP 45CrMoV的1/4,摩擦因数有所增大。 相似文献
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Shivakumar Nagavelly Vasu Velagapudi N. Narasaiah 《Transactions of the Indian Institute of Metals》2017,70(8):2155-2163
ZA-27 alloy is a lightest alloy which offers excellent bearing and mechanical properties in automobile and industrial applications. In this study, the MoS2 particles with 0.5, 1 and 1.5 (wt%) weight percentages were reinforced in ZA-27 alloy to form composites, which were fabricated by using ultrasonic assisted stir casting method. The ZA-27/MoS2 composite specimens were examined for chemical composition with the aid of XRD technique and EDS. Microstructure analysis of the ZA-27/MoS2 composites was studied using SEM. Tests were conducted for mechanical properties such as tensile strength and hardness on ZA-27/MoS2 composites samples as per ASTM standards. Dry sliding wear behavior of the composites was tested at various operating conditions by using pin-on-disc apparatus. Microstructural images of the ZA-27 composites reveal that there is a uniform dispersion of the MoS2 particles in the base material. From the results it is observed that the mechanical properties increases with ZA-27 reinforced with 0.5 wt% MoS2 composite and further decreases with increase in the filler content. The enhanced wear resistance is observed in ZA-27 reinforced MoS2 composites as compared to the unreinforced alloy. The wear rate of the ZA-27 composites decreases with the increase in filler content, further the worn surfaces as examined using SEM reveals the wear mechanism explaining the improved wear resistance of the particulate composites. 相似文献
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B. V. Cockeram 《Metallurgical and Materials Transactions A》2002,33(11):3403-3419
Iron-based weld hardfacing deposits are used to provide a wear-resistant surface for a structural base material. Iron-based
hardfacing alloys that are resistant to corrosion in oxygenated aqueous environments contain high levels of chromium and carbon,
which results in a dendritic microstructure with a high volume fraction of interdendrite carbides which provide the needed
wear resistance. The ferrite content of the dendrites depends on the nickel content and base composition of the iron-based
hardfacing alloy. The amount of ferrite in the dendrites is shown to have a significant influence on the hardness and galling
wear resistance, as determined using ASTM G98 methods. Fracture-toughness (K
IC) testing in accordance with ASTM E399 methods was used to quantify the damage tolerance of various iron-based hardfacing
alloys. Fractographic and microstructure examinations were used to determine the influence of microstructure on the wear resistance
and fracture toughness of the iron-based hardfacing alloys. A crack-bridging toughening model was shown to describe the influence
of ferrite content on the fracture toughness. A higher ferrite content in the dendrites of an iron-based hardfacing alloy
reduces the tendency for plastic stretching and necking of the dendrites, which results in improved wear resistance, high
hardness, and lower fracture-toughness values. A NOREM 02 hardfacing alloy has the most-optimum ferrite content, which results
in the most-desired balance of galling resistance and high K
IC values. 相似文献
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A dual composite of WC-Co 总被引:1,自引:0,他引:1
Zhigang Fang Greg Lockwood Anthony Griffo 《Metallurgical and Materials Transactions A》1999,30(12):3231-3238
Hardness, fracture toughness, and wear resistance are strongly inter-related properties of cemented tungsten carbide. Higher
hardness usually dictates higher wear resistance but at the cost of fracture toughness. A new dual composite of WC-Co, named
DC carbide, is reported in this article. The new, hybrid, particulate composite material has higher fracture toughness than
conventional WC-Co material at equivalent wear resistance. Moreover, it has higher wear resistance at equivalent fracture
toughness when compared to tool steels. The improved properties are achieved by the composite microstructure that maximizes
mean free path (MFP) between hard reinforcement particles. The new composite material is also unique in that the reinforcement
phase is a composite material in and of itself. 相似文献
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采用雾化喷射沉积成形技术制备了含10%(体积分数)Al2O3颗粒的18Ni(250)马氏体时效钢金属基复合材料.沉积坯件具有高致密度、增强颗粒均匀分布、无界面反应等组织特征.同基体合金相比,复合材料表现出加速时效行为.经热处理后复合材料的拉伸强度接近基体材料,耐磨性明显提高.采用显微力学探针技术研究了复合材料的时效行为,发现在Al2O3颗粒附近存在陡峭的弹性模量和硬度分布,是热错配应力造成的位错密度分布引起的析出相分布变化的结果. 相似文献