重载低速对高塑性锌合金磨损行为的影响

研究了一种延伸率为１０．３％的铸态高塑性锌铝合金在四种不同载荷和两种不同滑动速度下的摩擦磨损行为。试验表明：该合金在低滑动速度下的减摩性和耐磨性均随载荷的增加而呈谷底向抛物线变化，性能变化平缓，明显优于其在高滑动速度和高载荷下的摩擦摩损性能；在高滑动速度下，该合金的减摩性和耐磨性均随载荷的增加而急剧恶化。用剥层理论分析了试验结果，认为摩擦表面间的温度变化是导致不同滑动速度下合金摩擦磨损性能及其随载     

不同热处理下滑动速度对SiCp/Al复合材料摩擦学性能影响研究

SiCp/Al复合材料非匀质性微观结构使其摩损机制较传统匀质材料更为复杂,不同工况及热处理工艺下复合材料的摩擦学性能也存在差异。以SiCp/2024Al复合材料为研究对象,进行球-面接触干滑动摩擦磨损实验,探究它在不同热处理状态及滑动速率下的摩擦磨损性能及磨损机制。结果表明:热处理对复合材料力学性能和摩擦学性能有显著影响,固溶+人工时效态复合材料具有更高的强度、硬度及耐磨性;滑动速度影响复合材料的表面接触性质及磨损程度,摩擦因数和磨损量随滑动速度提高逐渐增大;随滑动速度增加,复合材料主要磨损机制由剥层磨损向磨粒磨损转变,而磨损机制的转变明显加快了复合材料的磨损,在实际应用中应尽量避免此现象发生。     

AS41耐热镁合金的摩擦学行为研究

研究了AS41耐热镁合金在室温和200℃时的显微组织、力学和摩擦学性能,探讨了其在高温的摩擦学机制。研究表明:AS41镁合金主要由基体(α-Mg相)和第二相(Mg17Al12、Mg2Si和MgO相)组成,在200℃时除伸长率有所增加外,抗拉强度和屈服强度均较室温时显著下降。AS41镁合金的摩擦因数随载荷增大而减小,滑行速度和滑行距离对摩擦因数影响不大;磨损率随着载荷和滑行距离的增加而增大,但随滑行速度的增加而减小;AS41镁合金在200℃的摩擦学性能优于其室温的。随着载荷变化,磨损机制发生变化;低载荷时表现为氧化磨损和磨粒磨损;中等载荷时表现为磨粒磨损和轻微剥层磨损;较高载荷时表现为剥层磨损。     

不同滑动速度下两种钛合金的磨损行为

采用销-盘式磨损试验机对比研究两种典型双相钛合金TC4和TC11合金在不同滑动速度下的磨损行为,并探讨了磨损机制。结果表明:TC4合金的磨损率随滑动速度加快和载荷增加而增长,滑动速度为4m/s时,同载荷下的磨损率达到了最高值;而TC11合金的磨损率随滑动速度加快先增加,在滑动速度为2m/s时达到最高值然后开始下降,在4 m/s时取得最低值。载荷30 N时,TC4合金在滑动速度为1～4 m/s时的磨损机制主要为轻微粘着磨损、磨粒磨损和剥层磨损;TC11合金在滑动速度为1～2 m/s时的磨损机制为轻微粘着磨损、磨粒磨损和剥层磨损,在3 m/s时的为氧化磨损和磨粒磨损,但在4 m/s时的为氧化轻微磨损。两种钛合金在滑动速度为1～2m/s时的磨损行为与磨损机制相似。但高速下,稳定摩擦氧化物层的存在显著降低了TC11合金的磨损率;而TC4合金由于硬度相对较低,对摩擦氧化物层的支撑作用不足,磨损率快速增长。     

两种TiAlN涂层的往复滑动摩擦学性能研究*

采用PLINT磨损试验机,对比考察了2种磁控溅射TiAlN涂层在往复滑动条件下的摩擦磨损性能.在摩擦动力学分析基础上,并利用扫描电子显微镜（SEM）、激光共焦显微镜（LCSM）、电子能谱（EDX）和X射线衍射XRD进行了微观分析,探讨了TiAlN涂层的摩擦磨损机理.结果表明：TiAlN涂层的摩擦学性能与涂层本身微结构密切相关;较低的摩擦因数对应着较好的耐磨性;涂层的往复滑动磨损表现为磨粒磨损、剥层和氧化磨损的共同作用的机制.     

生理盐水润滑下PEEK/WK复合材料的摩擦学性能

为研究生理盐水润滑条件下碳酸钙晶须含量、载荷大小、滑动速度因素对PEEK/CaCO3复合材料摩擦学性能的影响规律,并考察复合材料的摩擦学稳定性,在自制改性偶联剂处理晶须表面的基础上制备了PEEK/CaCO3复合材料,利用MMW1A立式万能摩擦磨损试验机对复合材料的摩擦学性能进行测试,用扫描电子显微镜(SEM)对磨损表面形貌进行扫描分析表征。结果表明,晶须含量对复合材料摩擦学性能影响明显,在0.9%的生理盐水润滑条件下PEEK/CaCO3复合材料随着晶须含量的增加,摩擦因数及比磨损率均呈现先减小后增大现象;当晶须质量分数为15%左右时,复合材料的摩擦因数达到最低值,同时比磨损量相对最低,复合材料与摩擦副的磨合过程相对平稳,具有较好的摩擦学性能,表现为粘着腐蚀磨损特征。外加载荷、滑动速度增大,材料的摩擦因数增大,比磨损率增加。     

SiC_p/Al基复合材料的摩擦磨损性能

在不同滑动速度和外加荷载参数下,对SiCP/Al复合材料干摩擦磨损性能进行研究。研究表明,随着外加荷载和滑动速度的增加,SiCP/Al复合材料的质量磨损率变化并不是单调的,而是呈现先降低后增加的趋势;另一方面,外加荷载为18 N,滑动速度为0.8059 m/s时,材料的摩擦系数最稳定,质量磨损率最小。在干摩擦磨损条件下,该复合材料的摩擦磨损机制由粘着磨损向磨粒磨损转变,最后出现严重的剥层磨损,有时还受两到三种磨损机制的共同作用。     

45钢干摩擦三维表面形貌特征研究

利用HST-100销-盘式摩擦磨损试验机考察干摩擦条件下45钢销试样的摩擦学性能,采用nanofocus三维表面轮廓测定仪检测其磨损表面形貌.研究表明,摩擦系数和表面高度偏差随滑动速度和载荷的变化存在一定的相关性,但二者随速度变化的相关性更强;陡峭度与复杂条件下摩擦系数呈线性变化,摩擦系数越大,陡峭度越大,尖峰宽度越小.     

(W,Mo)C-Al_2O_3复合材料室温往复滑动摩擦磨损性能

采用放电等离子烧结(SPS)方法,在较低的烧结温度(1550℃)下制备了(W,Mo) C-Al_2O_3复合材料。在HASR型往复摩擦磨损试验机上采用球盘式摩擦方式,对室温下(W,Mo)C-Al_2O_3复合材料与SiC陶瓷球对偶时的摩擦磨损试验结果进行分析,探讨了在干摩擦条件下滑动速度与载荷等摩擦磨损条件对摩擦副的摩擦因数影响规律,对摩擦盘的摩擦表面形貌与摩擦副的磨损机制进行分析。结果表明:(W,Mo)C-Al_2O_3合金试样随着滑动速度和载荷的增大,摩擦因数及磨损率总体呈下降趋势,平均摩擦因数值在0.2～0.6之间,磨损率数量级在10~(-6)～10~(-5)之间;随着滑动速度、载荷的减少,磨痕深度呈变浅趋势;随着载荷的增大,(W,Mo)C-Al_2O_3/SiC摩擦副的磨损机制从疲劳磨损和磨粒磨损为主转变为表面断裂和剥落机制为主。     

AZ71E镁合金的高温摩擦学行为(英文)

用销-盘摩擦磨损试验机考察 Z71E压铸镁合金在载荷为10~50 N时的高温摩擦学行为,利用光学显微镜(OM)和扫描电镜(SEM)对磨损表面和亚表面进行分析,通过光学显微镜(OM)、X射线衍射仪(XRD)、差示热扫描(DSC)等对AZ71E合金的高温微观结构、热稳定性和力学性能进行研究。结果表明:随着载荷和滑动距离的增加磨损率增大,而摩擦系数则随着载荷的增加而减少。在低载荷时,AZ71E镁合金的磨损机制主要是磨粒磨损;在150℃和高载荷下,粘着磨损和轻微的剥层磨损是主要的磨损机制;而在200℃及高载荷下,镁合金的主要磨损机制是严重的剥层磨损和熔融磨损。AZ71E镁合金的高温摩擦学性能提高的内在机制是AZ71E镁合金中第二相Al11Ce3使镁合金的高温拉伸和延展性能显著提高。     

激光熔覆TiC增强FeAl金属间化合物基复合材料涂层磨损性研究

利用激光熔覆技术在1Cr18Ni9Ti奥氏体不锈钢表面制得了以TiC为增强相、以FeAl 金属间化合物为基体的耐磨复合材料涂层，研究了激光熔覆。FiC／FeAl复合材料涂层在干滑动磨损条件下的耐磨性能及磨损机制。结果表明：随着载荷和滑动速率的增加，TiC／FeAl金属间化合物基复合材料涂层的磨损速率增加，其磨损机制随着载荷的增加逐渐由磨料磨损向粘着磨损转变；激光熔覆层中TiC体积分数的增加，一方面提高了涂层的磨料磨损抗力，另一方面降低了熔覆层表面与对磨材料之间的粘着倾向，提高了TiC／FeAl涂层的滑动磨损性能。激光熔覆TiC/FeAl金属间化合物基复合材料涂层具有优异的耐磨性能并随TiC体积分数的增加而提高。     

DEPENDENCE OF MICROSTRUCTURE SCALES OF EUTECTICS ON Ca-Si MODIFIER AMOUNT IN AUSTENITE STEEL COMPOSITES

Results presented in this paper contribute to investigation of the effect of the added Ca-Si modifier amount (αk) on the microstructure scales of granular γ-(Fe, Mn)3C eutectics such as the volume fraction (39 and diameter (d) in the austenite steel matrix composites (EAMC).Directional solidification of EAMC has been carried out using vertical Bridgman method at 50.6μms^-1 with a constant temperature gradient about 800Kcm^-1. The higher constitutional supercooling ahead of solid-liquid interface attributing to the larger αk results in the enlargement of γ-(Fe, Mn)3C coupled-zone and the increment of the nucleation rate of eutectics. Therefore, f increases with increasing αk. The branches of the primary austenite dendrites develop more greatly as αk increases, which limits the growth of eutectics. As a result, d decreases with increasing αk.     

Friction behavior of Al-Cu-Fe-B polycrystalline quasicrystals

Dry sliding friction between the polycrystalline Al59Cu25.5Fe12.5B3 quasicrystals(QCs) and coating of the diamond-like carbon(DLC) was carried out by self-made tribometer under different conditions. The influences of four parameters(temperature, sliding velocity, applied load, atmosphere) on friction of quasicrystal surface were studied. Microstructure of quasicrystal, morphology of worn surface, and wear debris were observed by scanning e-lectron microscope(SEM). The results show that for QCs, the friction coefficient and the roughness of worn surface is influenced by the parameters, especially greatly by the temperature. With increasing the applied load and sliding velocity, the friction coefficient decreases. The dominant wear mechanism at 350℃ is delamination for QCs. The cracks forms on the worn surface during friction. Moreover, phase transformation is not observed on worn surface of QCs at 350℃.     

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.     

Abrasive Wear Behavior of In Situ TiC Reinforced with Al-4.5%Cu Matrix

The present work deals with the investigation on weight loss and coefficient of friction of TiC reinforced Al-4.5%Cu in situ metal matrix composites. Experiments were conducted using pin-on-disc apparatus against abrasive paper by varying the applied load, sliding distance, and weight percentage of TiC. The results indicated significant improvement in the mechanical properties and wear resistance of experimental composites as compared to the parent metal matrix. The percentage of porosity though increased with increasing TiC reinforcement. The variation of weight loss of composites increased linearly with increasing applied load and sliding distance, whereas decreased with increasing weight percentage of TiC reinforcement. The coefficient of friction decreased linearly with increasing applied load and TiC reinforcement. SEM micrographs of worn surfaces show a well compacted transfer layer of wear debris along with wear track over the sliding surface. Grooves, delamination, and crack propagation were also observed in all test samples. The effective depth of penetration and size of debris was seen to reduce with increasing wt.% of TiC reinforcement in metal matrix.     

Structure,mechanical, and tribotechnical properties of an austenitic nitrogen steel after frictional treatment

The features of the structure and the mechanical and tribotechnical properties of an austenitic nitrogen steel (Cr16.5, Mn18.8, C0.07, N0.53, Si0.52 wt %, and Fe for balance) after frictional treatment have been studied. It has been shown that, along with twinning, the nitrogen austenite upon frictional treatment undergoes a γ → stacking fault → ε transformation. The strengthening of the steel by the frictional treatment manifests in a delay of the onset of the plastic flow. In the structure of the surface layer with a thickness of 5 μm, a high concentration of stacking faults has been detected. The mechanical properties depend on the orientation of the acting stresses relative to the direction of the frictional treatment. Upon the sliding friction of a ball made of hard alloy (94%WC + 6%Co) on the strengthened surface, an anomalously low coefficient of friction of 0.13 is observed. The coefficient of friction in the presence of abrasive particles in the form of wear debris increases to 0.50; however, the wear rate is almost two times lower compared to the same characteristic for a nonstrengthened surface of the nitrogen steel tested under the same conditions.     

粉煤灰/铝-镁合金复合材料的微观组织及摩擦磨损性能

采用粉末冶金法制得粉煤灰/Al-25%Mg复合材料,研究不同粉煤灰含量对复合材料微观组织、硬度和摩擦磨损性能的影响,采用扫描电子显微镜观察复合材料的磨损表面形貌,并对其磨损机制进行探讨。结果表明:随着粉煤灰含量的增加,复合材料的硬度呈现先增大而后减小的趋势;在较低粉煤灰含量和较低载荷下,该复合材料的摩擦因数均低于基体铝合金的,并且随粉煤灰含量的增加复合材料的耐磨性有所提高,复合材料的磨损机制主要为粘着磨损和磨粒磨损;在较高粉煤灰含量和较高载荷下,该复合材料的磨损机制转化为以剥层磨损和磨粒磨损为主。     

Wear Performance of Cu-Alloyed Austempered Ductile Iron

An investigation was carried out to examine the influence of structural and mechanical properties on wear behavior of austempered ductile iron (ADI). Ductile iron (DI) samples were austenitized at 900 °C for 60 min and subsequently austempered for 60 min at three temperatures: 270, 330, and 380 °C. Microstructures of the as-cast DI and ADIs were characterized using optical and scanning microscopy, respectively. The structural parameters, volume fraction of austenite, carbon content of austenite, and ferrite particle size were determined using x-ray diffraction technique. Mechanical properties including Vicker’s hardness, 0.2% proof strength, ultimate tensile strength, ductility, and strain hardening coefficient were determined. Wear tests were carried out under dry sliding conditions using pin-on-disk machine with a linear speed of 2.4 m/s. Normal load and sliding distance were 45 N and 1.7 × 10⁴ m, respectively. ADI developed at higher austempering temperature has large amounts of austenite, which contribute toward improvement in the wear resistance through stress-induced martensitic transformation, and strain hardening of austenite. Wear rate was found to depend on 0.2% proof strength, ductility, austenite content, and its carbon content. Study of worn surfaces and nature of wear debris revealed that the fine ausferrite structure in ADIs undergoes oxidational wear, but the coarse ausferrite structure undergoes adhesion, delamination, and mild abrasion too.     

Effect of austempering process on microstructure and wear behavior of ductile iron containing Mn-Ni-Cu-Mo

In this work, the effects of austempering time and temperature on the microstructure and sliding wear behavior of a Mn-Ni-Cu-Mo alloyed ductile iron were investigated. Ductile iron samples with the desired chemical composition were cast according to ASTM A897M-1990 Y-block. Wear test samples austenitized at 900 °C for 90 min, were austempered at 260, 290 and 320 °C for 30, 60, 90 and 120 min. The wear tests on samples were conducted by Block-on-Ring testing machine according to ASTM G77-98 standard, at the applied load of 75N and the displacement speed of 3.27 m/s. The results showed that the sample austempered at 260 °C for 90 min exhibited the maximum relative wear resistance in comparison with the as-cast sample. The X-ray diffraction patterns of wear debris and the SEM observations of worn surfaces and crosssection of worn surfaces together with wear debris showed that delamination associated with oxidation is the dominant wear mechanism in the samples.     

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。