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。     

耐铝及其合金熔体腐蚀磨损材料的研究进展（英文）

铝及其合金熔体引起的腐蚀磨损导致的材料失效是铝工业中一个非常普遍的难题。综述包括铁合金及陶瓷等材料在铝液中的腐蚀磨损行为及在液态金属中的腐蚀-磨损试验设备。在阐述单一的液态金属腐蚀和磨损机理的基础上,分析腐蚀磨损的协同效应。综合讨论由于摩擦副旋转导致的铝液动态搅拌、液态铝物理性质以及晶粒尺寸等因素对铝液腐蚀-磨损性能的影响。最后,总结耐铝液腐蚀磨损材料应该具备的基本特征。根据本课题组已有研究成果,特别是Ti Al3/Ti3Al C2/Al2O3这种金属/陶瓷复合材料的优异耐铝液腐蚀磨损性能,展望具有连续相互穿插结构陶瓷/金属复合材料在铝液腐蚀磨损环境中的应用前景。     

硼酸镁晶须增强6061铝基复合材料的干摩擦磨损行为(英文)

研究搅拌铸造工艺制备的硼酸镁晶须增强6061铝基复合材料在干滑动条件下的摩擦磨损性能。复合材料的体积分数为2%,根据增强体种类,材料分别记为:Al基体、Mg2B2O5w/6061Al、ZnO/Mg2B2O5w/6061Al和CuO/Mg2B2O5w/6061Al;讨论磨损速率和摩擦因数之间的关系。结果表明:在4种材料中,ZnO/Mg2B2O5w/6061Al复合材料的磨损率最低。随着载荷和滑动速度的增大,基体和复合材料的摩擦因数和磨损率降低,摩擦磨损机制由轻微磨损机制转向严重磨损机制。     

铝基复合材料的腐蚀与防护研究现状

对Cf/Al、SiC/Al、Al2O3/Al三种铝基复合材料的腐蚀研究现状和防护方法进行了讨论.Cf/Al复合材料以电偶腐蚀为主.SiC/Al 复合材料的腐蚀多发生在碳化硅纤维和铝基体的界面处,其原因是界面处的缝隙容易导致孔蚀和缝隙腐蚀,并最终可能造成表面剥层.Al2O3是绝缘体,与Al不存在电偶腐蚀,同SiC/Al和C/Al等相比具有更高的耐腐蚀性.目前提高铝基复合材料的防腐蚀性能的方法,主要包括铝基复合材料表面阳极氧化防护膜、表面化学钝化防护膜、其他表面涂镀层、增强体表面涂层、基体合金化等.最后展望铝基复合材料腐蚀与防护的研究和发展.     

两种铝合金活塞材料磨损行为研究

对两种铸造铝合金活塞材料的显微组织和不同工况下的磨损行为进行了对比研究。结果表明,两种活塞材料的微观组织均主要为α-Al相和初生硅,少量共晶硅呈针状或短棒状分布在α-Al枝晶晶界。活塞新材料因Fe元素的加入,出现新相Al0.5Fe3Si0.5,且共晶硅含量升高。干摩擦、边界润滑、含硫边界润滑、油润滑工况下两种材料的摩擦系数和磨损率均依次减小。同种磨损工况下,活塞新材料摩擦系数和磨损率更低。随着环境温度升高,干摩擦工况下磨损失效机理,由显微切削为主转变为氧化磨损和显微切削并存。含硫工况下,材料磨损性能明显改善,其磨损面呈现较好的釉质层,起到了明显的减磨作用。     

原位TiB2/Al复合材料摩擦磨损性能

研究了原位内生TiB2颗粒增强铝基(TiB2/Al)复合材料的摩擦磨损性能,并借助SEM对材料的磨损表面进行了分析.试验结果表明:复合材料的耐磨性优于基体铝.     

比较研究Si C和MoS_2对铝基复合材料磨损行为影响（英文）

为了提高纯铝对钢的干滑动摩擦耐磨性,通过压制烧结混合粉末的方法制备不同SiC、MoS_2和SiC/MoS_2颗粒含量的铝基复合材料。显微结构分析表明,该合金结构致密,这与密度和硬度测试结果相吻合。在恒定载荷和滑动速度下进行复合材料与对偶为AISI 52100钢的销-盘式磨损试验。结果显示,当Al/SiC和Al/MoS_2复合材料中增强相的最佳含量分别为10vol%和2vol%时,材料的磨损率最低;而Al/10SiC/_2MoS_2复合材料的磨损率和摩擦因数最低。扫描电镜观察表明,在纯铝中加入MoS_2颗粒后,材料的主要磨损机理由粘着磨损转变为以磨粒磨损为主。对于Al/SiC和Al/SiC/MoS_2复合材料,其主要的磨损机理为轻微的剥层磨损。Al/SiC/MoS_2复合材料与Al/SiC复合材料的摩痕和磨损表面接近,表明SiC颗粒在这两种复合材料摩擦学行为中起主导作用。     

Al3Ti/7075铝基复合材料磨损性能研究

研究了超声原位制备的Al3 Ti/7075铝基复合材料在不同载荷和滑动摩擦速度下的干摩擦磨损性能.采用SEM对磨损面和磨屑显微组织进行观察与分析,讨论了不同载荷下材料的磨损机制.结果表明:基体和复合材料磨损质量损失随着滑动摩擦速度和载荷的增加而增加.基体和复合材料都是从轻微磨损向严重磨损转化.当载荷为10～30N时,基...     

铝基复合材料粘结质量超声C扫描检测技术

采用超声C扫描水浸聚焦技术检测Al2O3纤维增强铝基复合材料活塞镶环粘结质量。设计制作Al2O3纤维增强铝基复合材料活塞模拟对比试样,利用模拟对比试样研究镶环粘结质量超声C扫描检测工艺。结果表明,超声C扫描水浸聚焦技术可实现对Al2O3纤维增强铝基复合材料活塞镶环粘结质量缺陷的定性、定位、定量检测。     

高含量B_4C/Al基复合材料磨损行为研究

对质量分数分别为20%、30%和40%的高含量B4C/Al基复合材料的磨损行为进行了研究,分析了颗粒含量、载荷变化以及磨损时间对该复合材料磨损性能的影响,探索了该复合材料磨损过程的微观机制。结果表明:B4C/Al基复合材料的磨擦系数随B4C含量的增加而减小,材料耐磨损性能随B4C硬质颗粒含量的增加而提高;随载荷从30 N增加到70 N,B4C/Al复合材料的磨擦系数先减小再增加,材料磨损速率随载荷增加而增大。随磨损进行,整个磨损过程体现出阶段性的变化,复合材料的摩擦系数先减小再增加,磨损速率先缓慢增大,然后较快增长。高含量B4C/Al基复合材料磨损过程主要表现为犁削磨损和黏着磨损的磨损方式,同时还伴随有氧化磨损机制。     

Thermal analysis and microscopic characterization of the piston alloy AlSi13Cu4Ni2Mg

In this research paper, the phases identified by thermal and microscopic analysis of the piston alloy AlSi13Cu4Ni2Mg, which was solidified under different conditions, are presented and compared with different piston alloys. Piston alloys are a group of casting Al–Si alloys, well-known as wear resistant materials, which are widely used as the piston materials for internal combustion engines because of their low thermal expansion coefficient and high wear resistance when alloyed with other elements such as copper, magnesium and nickel. Depending on the combination of alloying elements and other impacting factors, pistons alloys with different mechanical and physical properties are obtained.     

Thermal analysis of a ceramic coating diesel engine piston using 3-D finite element method

In this study, firstly, thermal analyses are investigated on a conventional (uncoated) diesel piston, made of aluminum silicon alloy and steel. Secondly, thermal analyses are performed on pistons, coated with MgO-ZrO₂ material by means of using a commercial code, namely ANSYS. Finally, the results of four different pistons are compared with each other. The effects of coatings on the thermal behaviors of the pistons are investigated. It has been shown that the maximum surface temperature of the coated piston with material which has low thermal conductivity is improved approximately 48% for the AlSi alloy and 35% for the steel.     

Tribological Properties of Al Alloy Particle Composites

In recent years, a variety of particle dispersed aluminum alloy composites have been synthesized. The tribological properties of these materials include sliding wear, friction, seizure resistance and abrasive wear (of composites containing solid lubricant as well as hard ceramic particles). The potential high-performance applications of Al-alloy-graphite composites include pistons for internal combustion engines and bearings. For such applications, the low stress abrasive wear rates of composites, containing high volume fractions (0.20–0.35), are comparable to that of heat treated 1045 steel.     

Plasma-Assisted Nitriding of Aluminum-Alloy Parts

Plasma-assisted nitriding of aluminum alloys promises to become a suitable alternative to variants of thermochemical treatment used for raising the wear resistance of these materials especially from the standpoint of the environmental effect. Process performed in vacuum with the use of nitrogen and an argon-hydrogen mixture as the process gas provides for the formation of a layer of compounds (aluminum nitrides) with enhanced hardness on various aluminum alloys. However, until the present the process has been used only at the laboratory scale. No data can be found in the literature, for example, on the effect of the batch size on the uniformity of the thickness of the nitrided layer or on the wear resistance of parts from aluminum alloys. The present work is a study of plasma-assisted nitriding of commercially produced parts (pistons) fabricated from an aluminum alloy. The parameters of the process are chosen after the determining optimum conditions for preliminary sputtering treatment. Special attention is devoted to provision of temperature uniformity within a batch and the possibility of improving the surface quality by increasing the thickness of the compound layer. The topography of the surface and the thickness, chemical composition, and hardness of the compound layer are studied by the methods of scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), metallography, and measurement of ultramicrohardness. The performance characteristics of untreated, nitrided, and anodized pistons are evaluated with the help of vibration wear tests with a rider fabricated from a standard material. The results of the tests show that the wear resistance of some nitrided pistons is comparable to that of anodized parts.     

海水环境中金属材料腐蚀磨损及耐磨防腐一体化技术的研究进展

随着"建设海洋强国"战略的实施,发展海洋装备、建设海洋工程成为推进和实施国家海洋战略的重要内容。鉴于海洋装备长期服役于海洋环境,因此海洋工程材料的腐蚀损伤是不可回避的关键问题,尤其是海洋装备中的运转部件,如海水泵、阀、海水液压传动系统、水下作业机器手、深海勘探和开采装备等面临腐蚀与磨损的耦合损伤。基于此,针对典型金属材料在海水环境中的腐蚀磨损失效行为及机理,综述了服役工况、腐蚀介质、电化学及材料因素对典型金属材料(如不锈钢、钛合金、铝合金、镍合金)在海水环境中腐蚀磨损性能的影响,综合分析了服役工况、腐蚀介质浓度、p H值、外加电位与材料性能之间的关系,阐明了金属材料腐蚀磨损过程中腐蚀、磨损及其交互作用。在此基础上,对比了一系列耐磨与防腐一体化涂层技术,如PVD涂层、热喷涂涂层、电镀涂层及聚合物粘结涂层的腐蚀磨损性能及典型应用,分析了耐磨与防腐一体化防护材料对腐蚀磨损性能的优化机理,以期为解决金属材料的腐蚀磨损问题提供有益借鉴。     

Evaluation offing surfaces with several coatings for friction, wear and scuffing life

Friction and wear of the sliding components in an automobile cause an increase in both fuel consumption and emission. Many engine components involved with sliding contact are all susceptible to scuffing failure at some points during their operating period. Therefore, it is important to evaluate the effects of various surface coatings on the tribological characteristics of the piston ring and cylinder block surface of a diesel engine. Wear and scuffing tests were conducted using a friction and wear measurement of the piston ring and cylinder block in a low friction diesel engine. The frictional forces, wear amounts and cycles to scuffing in the boundary lubricated sliding condition were measured using the reciprocating wear tester. The tester used a piece of the cylinder block as the reciprocating specimen and a segment of the piston ring material as the fixed pin. Several coatings on the ring specimen were used, such as DLC, TiN, Cr-ceramic and TiAlN, in order to improve the tribological characteristics of the ring. The coefficients of friction were monitored during the tests, and the wear volumes of the piston ring surfaces with various coatings were compared. Test results show that the DLC coating exhibits better tribological properties than the other coatings. The graphite structure of this coating is responsible for the low friction and wear of the DLC film. The TiN and DLC coatings show better scuffing resistance than the other coatings. The TiN and Cr-ceramic coated rings show good wear resistance and high friction.     

Al2O3短纤维/SiC颗粒混杂增强铝合金复合材料

研究了Ａｌ２Ｏ３ 短纤维和ＳｉＣ 颗粒混杂增强铝合金复合材料在制动过程中的摩擦磨损性能。结果表明复合材料在制动过程中的摩擦系数较稳定, 磨损量较小, 与传统的制动材料铸铁相比, 复合材料的表面温升较低, 铸铁由于表面温升较高而产生了大量的裂纹。复合材料由于增强体的存在, 制动过程中表面易形成致密连续的转移膜, 该转移膜的出现保证了复合材料在制动过程中摩擦系数的稳定, 降低了复合材料的磨损量。与铸铁相比, 复合材料的密度较低, 更适用于作制动材料     

车用柴油机缸套活塞磨损试验台设计

为研究南疆风沙环境中车用柴油机在不同沙尘浓度、工作速度、环境温度等条件下对发动机缸套活塞磨损的影响，设计柴油机缸套活塞磨损试验台。试验台主要由风沙输送装置、驱动传动装置、磨损测量及测试系统等组成，通过风沙输送装置模拟沙尘浓度、速度等参数变化的要求；设计的测控系统能够完成工作压力、环境温度、沙尘流量、转速等传感信息的收集和可视化。试验台采用动力机械常用的柴油发动机作为研究对象，适用于实验室中在研发缸套活塞耐磨材料时的测试装备。此试验机操纵方便，可拓展性强，可用于研究南疆风沙环境对内燃机磨损的规律、空滤的堵塞机制、进气阻力分析等。     

Low-cycle fatigue behavior of permanent mold cast and die-cast Al-Si-Cu-Mg alloys

Fatigue failure is one of the main failure forms of Al-Si-Cu-Mg aluminum alloys.To feature their mechanical aspect of fatigue behavior,the low-cycle fatigue behavior of permanent mold cast and die-cast Al-Si-Cu-Mg alloys at room temperature was investigated.The experimental results show that both permanent mold cast and die-cast Al-Si-Cu-Mg alloys mainly exhibit cyclic strain hardening.At the same total strain amplitude,the die-cast Al-Si-Cu-Mg alloy shows higher cyclic deformation resistance and longer fatigue life than does the permanent mold cast Al-Si-Cu-Mg alloy.The relationship between both elastic and plastic strain amplitudes with reversals to failure shows a monotonic linear behavior,and can be described by the Basquin and Coffin-Manson equations,respectively.     

仿生通孔形活塞裙部耐磨性能研究

目的为了减少发动机活塞裙部磨损,提高裙部耐磨性。方法基于仿生非光滑理论,以蚯蚓体表形态为仿生原形,在LX-2V型发动机活塞裙部设计出以孔的直径、每行孔间距、孔沿圆周角度为参数的仿生通孔形结构。采用正交设计方案对不同参数的仿生通孔形活塞进行有限元热结构耦合分析。以裙部最大变形量、裙部变形范围、裙部对称中心线上点与一侧点的应力差值作为评价活塞裙部耐磨性的标准,优选出模拟分析中耐磨性能良好的三个仿生活塞,并与标准活塞同时进行发动机台架磨损试验。结果合理的仿生通孔形结构可以有效减少活塞裙部磨损,提高裙部耐磨性。相对于标准活塞,当仿生活塞孔的直径为5 mm、每行孔的间距为6.5 mm、孔沿圆周角度为16°时,其耐磨性最大提高49%。结论过小的裙部最大变形量、过大的裙部变形范围,均不利于活塞裙部与缸套之间油膜的形成与保持,从而使活塞裙部磨损加剧。结合活塞裙部粗糙度值分析可知,合理的仿生通孔形结构可以优化裙部表面所受摩擦力,是进一步降低活塞裙部所受磨损的重要原因。