颗粒增强型铁基粉末冶金材料的研究现状

介绍了颗粒增强型铁基粉末冶金材料的特点及主要制备工艺,列举了几种有代表性的颗粒增强型铁基粉末冶金材料,并探讨了颗粒增强铁基粉末冶金材料的界面问题和磨损机理,展望了其应用前景。     

含铜铁基粉末冶金零件烧结性能的研究进展

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。     

粉末冶金颗粒增强钛基复合材料研究进展

颗粒增强钛基复合材料具有优异的力学性能，粉末冶金技术在制备颗粒增强钛基复合材料上有很大优势。本文从钛合金基材、颗粒增强相选择及制备工艺与性能等方面综述了粉末冶金颗粒增强钛基复合材料的研究进展，指出提高密度、降低成本是粉末冶金颗粒增强钛基复合材料的发展方向。     

粉末冶金法制备颗粒增强镁基复合材料的研究进展

概述了粉末冶金法制备颗粒增强镁基复合材料的研究进展, 介绍了颗粒增强镁基复合材料的常用基体和微米级、纳米级增强体。重点阐述了粉末冶金法制备颗粒增强镁基复合材料的工艺, 包括增强体预处理工艺、混合粉体成形工艺及烧结工艺。总结了粉末冶金制备工艺对复合材料组织与力学性能的影响规律, 包括增强体-基体界面结合情况的研究和颗粒增强体强化机制的探究。最后, 对粉末冶金法制备颗粒增强镁基复合材料的发展前景进行了展望, 并提出改进措施。     

粉末冶金原位合成法制备钛基复合材料的研究进展

本文从制备钛基复合材料所需的基体和增强体的选材出发,阐述了粉末冶金方法在颗粒增强钛基复合材料中的研究与应用,并就未来粉末冶金技术在颗粒增强钛基复合材料中的研究方向阐明了观点。     

高强度铁基粉末冶金结构材料研究成功

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     

粉末冶金铁基材料烧结中应用氮基气氛获得成功

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     

Ni、P元素对于铁基粉末冶金材料力学性能的影响

采用粉末冶金方法制备铁基烧结材料,并测试材料的硬度和压溃强度,考察了Ni、P元素对于铁基粉末冶金材料密度和力学性能的影响.结果表明:Ni不仅可以提高铁基材料中珠光体的含量,还可以显著提高材料的硬度和压溃强度,当Ni含量为3％时效果最好;添加微量P元素可以明显提高含Ni铁基材料的硬度和压溃强度,但当P含量超过0.15％后,对材料硬度的提升作用减缓,而材料的压溃强度则大幅下降.     

铁基粉末冶金烧结材料的疲劳与失效行为研究进展

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.     

粉末冶金法制备颗粒增强钛基复合材料的研究进展

颗粒增强钛基复合材料因具有高强度、轻量化、耐蚀性和高温力学性能优良等特点被广泛应用于航空航天、汽车工业、医用工程领域。本文介绍了钛基复合材料在国内外的发展概况与研究成果,阐述了钛基复合材料基体组成、增强体形貌及物理性质、增强体引入方式、制备工艺及力学性能等方面,重点讨论了利用不同粉末冶金法制备颗粒增强钛基复合材料的工艺特点及材料特性,并对其进一步研究提出展望。     

The features of influence of ZrO2 and WC nanodispersed additives on the properties of metal matrix composite

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.     

铁基非晶合金涂层的研究进展

铁基非晶合金涂层以其良好的力学性能、 优异的耐磨耐蚀性以及较低的经济成本已成为较有前景的非晶涂层材料之一。 本文综述了铁基非晶涂层材料的设计准则与材料体系, 介绍了激光熔覆技术和热喷涂技术制备铁基非晶涂层的进展和发展趋势, 结合铁基非晶涂层的性能特点介绍了其工程应用概况。 指出了目前铁基非晶涂层研 究领域存在的问题并展望了发展方向。     

热喷涂Fe基非晶合金涂层的微观结构与摩擦磨损行为

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.     

Mechanical Properties and Dry Sliding Wear Behaviour of Molybdenum Disulphide Reinforced Zinc–Aluminium Alloy Composites

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.     

热等静压法制备NbC颗粒增强45CrMoV复合材料的组织与性能

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。     

Some observations of the influence of δ-ferrite content on the hardness,galling resistance,and fracture toughness of selected commercially available iron-based hardfacing alloys

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.     

激光熔覆改性铁基合金涂层的硬度和耐磨性能研究

为提高石油钻井行业中工件表面涂层的硬度和耐磨性,提升工件使用寿命,本文设计开发了含Cr、V元素的三种铁基激光粉末,通过激光熔覆加工工艺进行涂层制备,对铁基激光涂层的物相、硬度和摩擦磨损性能检测,成功开发了硬度高达60 HRC,摩擦系数为0.6094,15分钟50N载荷条件下磨损量仅为0.0007 g的高耐磨铁基激光熔覆涂层,满足石油钻井行业对于高硬度、高耐磨、长寿命的涂层需求。     

A dual composite of WC-Co

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.     

WC颗粒增强对Fe-1.5Cu-1.8Ni-0.5Mo-1C粉末冶金复合材料的影响

制备了含有不同质量分数WC增强颗粒（0%、1%、2%、3%、4%、5%、6%、7%、8%、9%及10%）的Fe-1.5Cu-1.8Ni-0.5Mo-1C粉末冶金复合材料,分析了WC质量分数对复合材料显微组织、硬度与耐磨性能的影响。结果表明,在Fe-1.5Cu-1.8Ni-0.5Mo-1C材料中添加适量的WC颗粒可以提升复合材料的性能,尤其是耐磨性能。当WC颗粒的质量分数在1%~2%时,材料具有较好的组织结构与力学性能,相对于不添加WC增强颗粒的材料,含质量分数1%与2% WC增强颗粒的材料硬度（HRB）分别提升了12.9%和14.3%,磨损量分别降低了50%和52.1%。