铬对铁基预合金粉末烧结组织和性能的影响

采用冷压烧结方法制备Fe-Ni-Mo-Cu-Cr系铁基粉末冶金材料,研究了铬对粉末烧结密度、微观组织特征及耐磨性能的影响,并借助于扫描电镜观察分析磨损形貌、探讨其摩擦磨损机制。结果表明,添加少量铬的Fe-Ni-Mo-Cu预合金粉末,在1120℃下烧结,可获得较高的烧结密度；微观组织硬度随铬量的增加而增加,表观硬度随密度的增加而增加。干滑动摩擦磨损率随磨损滑移距离的增加先增加而后逐渐降低,磨损机制主要为粘着磨损和氧化磨损。     

铬对铁基预合金粉末烧结组织和性能的影响

采用冷压烧结方法制备Fe-Ni-Mo-Cu-Cr系铁基粉末冶金材料，研究了铬对粉末烧结密度、微观组织特征及耐磨性能的影响，并借助于扫描电镜观察分析磨损形貌、探讨其摩擦磨损机制。结果表明，添加少量铬的Fe-Ni-Mo-Cu预合金粉末，在1120℃下烧结，可获得较高的烧结密度；微观组织硬度随铬量的增加而增加，表观硬度随密度的增加而增加。干滑动摩擦磨损率随磨损滑移距离的增加先增加而后逐渐降低，磨损机制主要为粘着磨损和氧化磨损。     

淬火保温时间对GCr15轴承钢组织与摩擦磨损性能的影响

采用高温箱式电阻炉对退火态GCr15轴承钢进行了淬火和低温回火处理,采用光学显微镜、X射线衍射仪和洛氏硬度计对其经不同淬火保温时间处理后的显微组织、残留奥氏体含量和硬度进行了分析,并利用UMT-2摩擦磨损试验机在干摩擦条件下对GCr15钢进行滑动摩擦磨损试验,采用扫描电镜、能谱仪、三维形貌仪对其磨损率和磨损机制进行分析,研究淬火保温时间对GCr15轴承钢显微组织、力学性能和摩擦磨损性能的影响.结果 表明:GCr15轴承钢经淬火和回火处理后的组织由回火马氏体、残留奥氏体和碳化物组成.随着淬火保温时间的延长,GCr15轴承钢的残留奥氏体含量和硬度均呈现先增加后减小的趋势,而碳化物平均尺寸先减小后增加,保温时间为60 min时,碳化物的数量急剧减少;淬火保温时间对GCr15轴承钢摩擦系数影响不大,保温40 min时磨损率最小,20 min时磨损最严重.磨痕表面粘着磨损与氧化磨损共存,保温40 min时,磨痕表面剥落坑相对较小,剥落最轻微.     

铁基高密度烧结材料的摩擦磨损性能研究

采用烧结热锻工艺获得高密度和高硬度的铁基粉末烧结冶金材料,研究了铁基粉末中的铬含量和施加在烧结材料上的载荷对材料摩擦磨损性能的影响,并借助于扫描电镜观察和分析了粉末冶金烧结材料的磨损形貌、探讨其摩擦磨损机制.结果表明,在铁基粉末中加入0.6%铬时,该粉末材料的硬度、密度和耐磨性最好.主要磨损机制为氧化磨损、粘着磨损和磨粒磨损.     

载电条件下30%Mo/Cu-Al2O3复合材料的摩擦学行为

采用真空热压烧结-内氧化法,制备了30%Mo/Cu-Al2O3复合材料。在载电条件下,考察了30%Mo/Cu-Al2O3销试样和铬青铜QCr0.5盘试样摩擦副的滑动摩擦磨损性能,利用扫描电镜观察磨损形貌并探讨了其摩擦磨损机制。结果表明,Mo颗粒的加入,增加了复合材料的整体强度及耐磨性;电流对磨损率和摩擦系数具有显著影响,随着电流增加,30%Mo/Cu-Al2O3复合材料的磨损率增加,摩擦系数增大;其磨损机制主要为磨粒磨损、粘着磨损和电烧蚀磨损。     

热处理对42CrMo制动盘摩擦磨损性能的影响

以自卸42CrMo调质钢制动盘为研究对象,对其进行了不同的热处理。采用MG-2000型销-盘摩擦磨损试验机研究了不同摩擦条件下热处理对试样的摩擦磨损性能的影响。并采用FEI Quanta 200型扫描电镜对试样的磨损表面形貌进行表征。结果表明:不同热处理状态的42CrMo制动盘试样的摩擦系数均随转速和接触压力的增大而减小;磨损率随转速和接触压力的增大而增大;在相同摩擦条件下,840℃淬火+400℃回火处理的销试样的摩擦系数和磨损率均最小;在低速低载时,42CrMo钢的磨损机制主要是磨粒磨损,高速高载时,其磨损机制主要是粘着磨损;转速500r/min比300 r/min的试样发生严重磨损的时间短。     

铬对FeNiMo系粉末冶金烧结性能的影响

研究了铬对Fe-Ni-Mo系粉末烧结密度、微观组织特征及耐磨性能的影响,通过SEM观察分析了磨损形貌,探讨了其摩擦磨损机制.结果表明,烧结密度随铬量的增加而变化,最佳的铬添加量为0.6%;在1120℃冷压烧结条件下,含铬的烧结组织晶粒细小,且随铬量的增加由珠光体转变为索氏体;在干滑动摩擦过程中,磨损机制主要为氧化磨损和粘着磨损.     

Mg-11Y-5Gd-2Zn镁合金干滑动的摩擦磨损行为

采用往复式摩擦磨损试验机对铸态和T6态Mg-11Y-5Gd-2Zn合金进行干摩擦磨损试验,研究载荷（3~15N）、磨擦速度（0.03~0.24m/s）、摩擦温度（25~200 °C）对合金磨损率的影响,并通过扫描电镜观察合金磨损表面形貌和磨屑。结果表明：随着载荷的增加,合金的磨损率几乎呈线性增加;随着摩擦速率的增加,合金的磨损率降低;铸态合金的磨损率高于T6态合金的。Mg-11Y-5Gd-2Zn合金中的Mg12Y1Zn1相、表面氧化相和残留的磨屑影响合金的磨损率。在本试验条件下,磨损机制主要是粘着磨损和塑性变形。     

不同载荷下GCr15钢的滑动摩擦磨损性能

采用光学显微镜、X射线衍射仪、洛氏硬度计等对淬-回火后GCr15轴承钢的显微组织、残留奥氏体含量和硬度进行分析,并利用UMT-2摩擦磨损试验机在干摩擦条件下对GCr15钢进行了变载滑动摩擦磨损试验,采用扫描电镜、能谱仪、三维形貌仪研究了载荷对GCr15钢的滑动摩擦磨损性能的影响。结果表明:淬-回火后的GCr15轴承钢的显微组织由回火马氏体、残留奥氏体以及碳化物组成,其组织特征呈典型的"黑白区"形貌,残留奥氏体含量约为12.5%,硬度约为62 HRC;GCr15轴承钢的摩擦系数随着载荷的增加而减小,磨痕宽度和磨损率随着载荷的增加而增大,磨损机制主要为粘着磨损与氧化磨损的混合,且随着载荷的增大,粘着与氧化程度加剧。     

干摩擦与边界润滑下SiC/Al复合材料的摩擦磨损性能

采用机械合金化和热压烧结相结合的方法分别制备了w(Si C)分别为3%、5%、7%的铝基Si C/Al复合材料。研究了Si C/Al复合材料的显微组织和硬度。结果表明:当w(Si C)=5%时,复合材料显微组织最为细小、均匀。随着Si C含量的升高,硬度呈现先增加后减小趋势,且当w(Si C)=5%时,硬度达到最大值57. 75 HB。不同Si C含量铝基复合材料在室温干摩擦和边界润滑两种工况中的摩擦磨损性能表明:随着Si C含量的升高,复合材料磨损率和摩擦因数均呈先减少后增加的趋势,w(Si C)=5%的复合材料的磨损率和摩擦因数均最小,且边界润滑工况中材料磨损率和摩擦因数均小于干摩擦工况的;观察不同Si C含量的Si C/Al复合材料的磨损面及其磨屑形貌可以看出,干摩擦工况中,材料主要磨损机制为磨粒磨损和粘着磨损,而在边界润滑工况中,其主要磨损机制为磨粒磨损和轻微氧化磨损。     

Improvement of wear resistance of wire drawing rolls with Cr-Ni-B-Si + WC thermal spraying powders

In wire drawing process, wear of rolls must be considered because of wear that influences the economics of the forming process. In this study, a nickel based matrix reinforced with WC was deposited by low cost powder welding method on low carbon steel substrates in order to determine the wear resistance of wire drawing rolls. Powder welding method includes, contrary to plasma and high velocity oxyfuel (HVOF) spraying methods, the advantages such as the single operation of powder application-fusion, simplicity, cheapness, and the ease of application. Blends of NiCrBSi and WC powders were prepared in weight proportions of WC of 40%, 45%, 50%, 55%, and 60%, respectively. Wear performance of these coatings was investigated by the dry sliding wear experiments. The wear resistance of the metal matrix composite coatings is dependent on the amount of WC. From 40% to 60%, the increase of WC is very effective on the wear resistance. The coatings with 55% and 60% of WC were worn less than the other coatings. From 55% to 60%, further increase of WC was found not to be effective for the best wear resistance. The microscopic studies of WC particles and Ni-based matrix were characterized by the scanning electron microscopy (SEM). The SEM analysis on the worn surface of coated samples shows that the matrix is considerably worn while WC particles are not considerably worn at the beginning of the wear testing. Additionally, WC particles effectively provide protection for achievement of the wear resistance at advanced periods of the wear testing.     

Microstructure and dry sliding wear resistance of CoTi intermetallic alloy

A wear resistant CoTi intermetallic alloy was fabricated by the laser melting deposition process. Microstructure of the alloy was characterized by OM, SEM, XRD and EDS and wear property was evaluated under room-temperature dry sliding wear test condition. Wear resistance of the CoTi intermetallic alloy under dry sliding wear test condition is up to 2 and 3.3 times higher than the hardened high-speed steel W18Cr4V and the bearing steel 1.0%C–1.5%Cr, respectively. The excellent wear resistance of the CoTi alloy is attributed to the inherent good toughness and strong yield-anomaly of the intermetallic CoTi as well as to the unique strong friction-induced hardening in the worn surface and subsurface of CoTi alloy under dry sliding wear process.     

氩弧熔敷原位自生TiCp/Ni60A复合材料组织和耐磨性

利用氩弧熔敷技术在16Mn钢表面原位合成TiC增强Ni基复合材料耐磨涂层.采用XRD、SEM等手段分析涂层的组织,测试涂层的室温干滑动磨损性能.结果表明:其室温干滑动磨损机制为显微切削磨损,熔敷层与基体呈冶金结合,TiC颗粒均弥散分布于熔敷层中.涂层有较高的硬度,在室温干滑动磨损试验条件下具有优异的耐磨性.     

挤压态AZ61镁合金磨损性能研究

主要研究了挤压态AZ61镁合金在不同载荷和滑动摩擦速度条件下的磨损性能。采用SEM对磨损面进行显微组织观察与分析,讨论了不同载荷下材料的主要磨损形式。结果表明,磨损质量损失随着滑动摩擦速度和载荷的增加而增加。挤压态AZ61镁合金的磨损机制主要分为轻微磨损和严重磨损。轻微磨损主要是擦伤磨损、氧化磨损与剥层磨损,在磨损面上形成的擦痕与裂纹,其磨损程度较轻,磨损面积小;当载荷增加到100N和120N时,塑性变形和熔化在磨损面形成的磨痕较深且磨损面积大,表现为严重磨损。     

激光熔覆Mo2Ni3Si／NiSi金属硅化物复合材料涂层组织与耐磨性

以39Mo-35Ni-26Si(w％)合金粉末为原料，采用激光熔覆技术，在1Cr18Ni9Ti不锈钢基材表面翩得以Mo2Ni3Si金属硅化物为初生相，以Mo2Ni3Si／NiSi共晶相为基体的金属硅化物耐磨复合材料涂层。涂层的常温干滑动磨损试验结果表明，在磨损过程中，Mo2Ni3Si／NiSi共晶相轻微地优先磨损，Mo2Ni3Si金属硅化物微微凸出于磨损表面，起到抗磨的骨干作用。由于Mo2Ni3Si金属硅化物具有很高的硬度和很强的原子间键合力，在磨损过程中难于变形和粘着，激光熔覆Mo2Ni3Si／NiSi金属硅化物复合材料涂层具有优异的耐磨性，与1Cr18Ni9Ti标样相比，涂层的耐磨性提高了56倍。     

Dry friction and wear characteristics of MoSi2 against ahoy steels

The dry friction and wear characteristics of three kinds of friction couples under different loads, MoSi2/45 tempered steel, MoSi2/45 quenched steel, and MoSi2/CrWMn steel, were investigated by using a friction and wear tester. SEM and X-ray diffraction were employed to analyze the microphotograph of the worn surface and the phase of worn pieces in order to reveal the wear mechanisms of MoSi2 material. The results show that MoSi2/CrWMn steel friction pair has good dry friction and wear properties under the load of 80 N, where the friction coefficient is 0.255 and the wear rate of MoSi2 is only 14.72 mg.km-1. But under the load of 150 N, it is MoSi2/45 tempered steel friction pair that has good tribological properties,MoSi2 under low loads is brittle fracture. With the increase of load, the main wear mechanism of MoSi2 against 45 quenched steel or CrWMn steel is adhesive wear. However, the wear mechanism of MoSi2 against 45 tempered steel is changed from oxidation-fatigue wear to adhesive wear.     

NiCrBSiWCe合金粉末喷熔层滑动磨损特性研究

采用热喷熔方法在45钢表面制备了NiCrBSiWCe合金粉末喷熔层,在SRV磨损试验机上进行小振幅滑动磨损试验研究.结果表明,NiCrBSiWCe合金喷熔层的摩擦磨损性能明显高于SAE52100钢.在较低载荷和滑动速度较低下,小振幅滑动磨损机理为磨损表面的划痕、裂纹和疲劳脱层.而在较高滑动速度下,小振幅滑动磨损机理为磨损表面的氧化磨屑层的形成,含稀土的磨屑层阻碍了喷熔层小振幅滑动磨损.     

Dry sliding wear of cryotreated multiple tempered D-3 tool steel

Wear test using pin-on-disc machine was used to investigate the role of multiple tempering after cryogenic treatment of D-3 tool steel. Conventional quenching (950 °C) and tempering (150 °C) treatments were given along with intermediate cryogenic treatment (?185 °C). Specimens were subjected to wear tests on pin-on-disc machine in dry sliding condition for sliding distance of 6000 m at 5.5 kg load and for sliding speed of 3.0 m/s. Hardness data, microstructures, wear loss and SEM analysis of worn surface throw light on the underlying metallurgical mechanism responsible in improving wear resistance property of the D-3 tool steel.     

Wear properties of nonhydrogenated,hydrogenated,and dehydrogenated Ti6A14V alloy

Wear properties of the nonhydrogenated,hydrogenated 0.5 wt% and dehydrogenated Ti6 A14 V alloys were studied through dry sliding wear tests using an M-200 type pin-on-disk wear testing machine in ambient air at room temperature to reveal the effects of hydrogen on wear properties of Ti6 A14 V alloy. Morphology and chemical element of worn surface were investigated by means of scanning electron microscope(SEM) and energy dispersive spectroscopy(EDS). Results show that hydrogen decreases the wear resistance of Ti6 A14 V alloy. Wear rate of the Ti6 A14 V alloy increases after hydrogenation. Wear rate increases by 244.3 % when 0.5 wt% hydrogen is introduced into a Ti6 A14 V alloy. Wear rate of the dehydrogenated Ti6 A14 V alloy recovers. Wear mechanisms of the nonhydrogenated, hydrogenated, and dehydrogenated Ti6 A14 V alloys are determined. The nonhydrogenated Ti6 A14 V alloy is controlled by oxidative wear. The hydrogenated Ti6 A14 V alloy is dominated by abrasive wear. Wear mechanism of the dehydrogenated Ti6 A14 V alloys is a mixture of oxidative wear and abrasive wear.     

高钒高速钢干滑动磨损性能研究

利用MM-200型滑动磨损试验机测试了高钒高速钢在不同压力下的干滑动磨损性能，借助于扫描电镜对其磨损形貌和组织进行观察，并与高铬铸铁对比考察了其耐磨性和磨损机理。结果表明：高钒高速钢的耐磨性明显优于高铬铸铁，其磨损机理为犁削磨损和疲劳磨损的复合，并且有应力作用下碳化物的脆性碎裂及脱落。