Effects of Yttria Addition on Microstructure,Mechanical Properties,Wear Resistance and Corrosive Wear Resistance of TiNi Alloy

TiNi alloy has a high resistance to wear and could be an excellent candidate for various tribological applications. But studies show that oxygen active elements can improve properties of some alloys,markedly.Yttrium is one of the oxygen active elements.In this paper,the e-ects of yttria addition on properties of TiNi have been studied via micro-indentation,hardness,wear and corrosive wear tests.It is demonstrated that by addition of yttria to 5%,TiNi alloy can own improved mechanical properties and resistan...     

Beneficial effects of yttrium on mechanical failure and chemical stability of the passive film in 6061 aluminum alloy

Recent studies demonstrated that oxygen-active elements such as yttrium improved the resistance of some alloys to wear and corrosive wear. In this work, the breakdown of passive film and chemical resistance of the passive film in Y-free and Y-containing 6061 aluminum alloy samples were studied. It was demonstrated that critical load that caused failure of the passive film on Y-containing specimens was higher than Y-free samples. Also, penetration depth showed that indentation resistances of Y-containing samples were less than Y-free samples. Polarization behavior of Y-containing samples was improved in contrast of Y-free samples in water and acid environments. Y-containing samples had more power to stabilize the oxide film and make it more inert to electron transfer. Results showed that there was an optimum yttrium addition for improving the properties of Al 6061. Results showed that the best percent of yttrium addition was between 1.5 and 4% and more than this the properties of alloy did not improved     

New wear-resistant material: Nano-TiN/TiC/TiNi composite

Near-eqiatomic TiNi alloy has been found to exhibit high resistance to wear, especially to erosion. The high wear resistance of the alloy may largely benefit from its pseudoelasticity. Recent studies demonstrate that the wear resistance of TiNi alloy can be considerably enhanced when hard particles such as TiC were added as a reinforcing phase. It was expected that the wear resistance of such a composite could be further improved if the TiNi matrix can be strengthened with retained pseudoelasticity. Attempt was made to develop such a tribo composite, using nano-TiN powder to strengthen the matrix of the TiC/TiNi composite. The composite was made using a vacuum sintering process. Sliding wear behavior of this material was evaluated. It was demonstrated that the nano-TiN/TiC/TiNi composite exhibited excellent wear resistance, superior to those of the TiC/TiNi composite and WC/NiCrBSi hardfacing overlay. In order to understand the role of the nano-TiN powder, localized mechanical behavior and micro-scale wear of the TiNi matrix with and without nano-TiN powder were investigated using a triboscope. Worn surfaces were examined using SEM to better understand the wear mechanism and to find out clues for further development.     

Variations in Wear Resistance of a Novel Triboalloy-Pseudoelastic TiNi Alloy - with Respect to its Pseudoelasticity and Hardness

It has recently been found that TiNi shape memory alloy has another attractive property: high resistance to wear. The wear resistance of this alloy benefits from its pseudoelasticity (PE). It has, however, been noticed that other mechanical properties also affect the wear resistance, especially the hardness. Research was conducted to investigate the correlation between the wear resistance and both the PE and hardness. It has been demonstrated that when the PE is high, lower hardness leads to higher wear resistance.     

Development of novel wear-resistant materials: TiNi-based pseudoelastic tribomaterials

Extensive research has being conducted at the University of Alberta to investigate the wear behavior of pseudoelastic TiNi alloy during several wear processes, including erosion, corrosive erosion, and sliding wear. The research demonstrates that this novel wear-resistant alloy is multi-functional and could be an excellent candidate for various wear applications. Attempts have also been made to develop tribo-composites using the TiNi alloy as the matrix reinforced by hard ceramic particles. This paper presents a brief review of our recent progress in developing this novel tribo-material as well as in exploring the correlation between the pseudoelasticity and the wear resistance.     

Study of effect of aging on martensitic transformation and tribological properties of TiNi alloy using DSC,neutron diffraction,and micromechanical probing techniques

Abstract

Recent studies have demonstrated that TiNi shape memory alloy exhibits excellent wear resistance, benefiting from their pseudoelasticity (PE) due to a thermoelastic martensitic transformation. The maximum wear resistance of the alloys corresponds to an optimum balance between the PE and hardness, which is strongly influenced by heat treatment. In this work, the effect of aging treatment on martenstic transformation behaviour, mechanical properties, including the pseudoelasticity and hardness, and wear behaviour of a Ti–51 at.-%Ni alloy was investigated using differential scanning calorimetry, neutron diffraction, and micromechanical probing techniques. The main objective of the study was to understand the aging effect on wear behaviour of the TiNi alloy and explore the mechanisms involved for further improvement of this novel tribo-alloy.     

Wear characteristics of spray formed Al-alloys and their composites

In the present investigation, different Al based alloys such as Al–Si–Pb, Al–Si, Al–Si–Fe and 2014Al + SiC composites have been produced by spray forming process. The microstructural features of monolithic alloys and composite materials have been examined and their wear characteristics have been evaluated at different loads and sliding velocities. The microstructural features invariably showed a significant refinement of the primary phases and also modification of secondary phases in Al-alloys. The Pb particles in Al–Si–Pb alloy were observed to be uniformly distributed in the matrix phase besides decorating the grain boundaries. The spray formed composites showed uniform distribution of SiC particles in the matrix. It was observed that wear resistance of Al–Si alloy increases with increase in Pb content; however, there is not much improvement after addition of Pb more than 20%. The coefficient of friction reduced to 0.2 for the alloy containing 20%Pb. A sliding velocity of 1 ms⁻¹ was observed to be optimum for high wear resistance of these materials. Alloying elements such as Fe and Cu in Al–Si alloy lead to improved wear resistance compared to that of the base alloy. The addition of SiC in 2014Al alloy gave rise to considerable improvement in wear resistance but primarily in the low pressure regime. The wear rate seemed to decrease with increase in sliding velocity. The wear response of the materials has been discussed in light of their microstructural features and topographical observation of worn surfaces.     

TiNi合金化学抛光工艺及其对耐蚀性的影响

对ＴiNi合金化学抛光液的组成和抛光工艺进行了研究和优化发现,化学抛光的质量不仅与抛光液配和抛光工艺直接相关,还与ＴiNi合金的处理状态有关,冷轧态固溶及退火态易获得低的表面粗糙度,用电化学方法测试了化学抛光与机械抛光试样的阳极极化曲线,结果表明,化学抛光能提高ＴiNi合金的点蚀电位（Ｅb) ,降低再钝化电位（Ｅrp)从而显著提高其耐蚀性,使化学抛光的表面达到镜面状态。     

AlNP/Al和TiB2P/Al复合材料摩擦磨损性能研究

研究了油润滑条件下两种不同铝基复合材料及其基体合金的摩擦磨损性能,分析了增强体对材料摩擦磨损性能的影响以及相应的磨损机理.结果表明:油润滑条件下,随着摩擦时间的延长,AlNP/Al复合材料的摩擦系数由小变大趋于稳定;而TiB2P/LY12复合材料的摩擦系数却是由大变小趋于稳定,这主要与其摩擦过程中形成凹坑产生润滑油膜有关.由于增强体强度的增加,50%(体积分数,下同)TiB2P/Al复合材料的摩擦系数低于50%AlNP/Al复合材料,且耐磨性优于50%AlNP/LY12复合材料.增强相的加入显著提高了材料的耐磨性,使得复合材料的抗粘着能力明显优于基体合金.     

2024铝合金微弧氧化涂层的耐磨性能

为了提高2024铝合金的耐磨性,对其进行微弧氧化。利用扫描电镜(SEM)和X射线衍射仪(XRD)分析了涂层的微观组织结构和物相组成;采用高速往复摩擦磨损试验机对2024铝合金微弧氧化涂层在不同载荷下的磨损性能进行了研究,并采用白光三维形貌仪进行磨损形貌分析及磨损体积计算。结果表明:2024铝合金微弧氧化涂层是一种微孔结构,涂层相主要成分为α-Al_2O_3、γ-Al_2O_3,且Al_2O_3具有高硬度、耐磨损的优良特性,有利于提高铝合金的耐磨损性能;微弧氧化涂层的摩擦系数随着载荷的增加而减小,而磨损量随载荷的增加而增加,磨损机理为磨粒磨损。     

Wear behaviors and wear mechanisms of wrought magnesium alloy AZ31 fabricated by extrusion-shear

Extrusion-Shear (ES) process for magnesium alloy is a newly developed plastic deformation technique which combines direct extrusion (DE) with ECAP (equal-channel angular pressing). Grains of ES-processed magnesium alloys can be refined effectively and mechanical properties can be improved, but the tribological properties have not been studied. In this study, the wear behaviors and wear mechanisms of AZ31 magnesium alloy samples produced by direct extrusion (DE) and extrusion-shear (ES) technologies, respectively, have been evaluated by fiction coefficient and wear frequencies obtained from the dry sliding tests conducted at different loads and frequencies by using a high speed dry sliding test machine. SEM and EDS analyses technologies also have been used to analyze the wear surfaces and wear debris in different fiction conditions. Based on the results, the ES-processed samples show a better wear resistance than those prepared by DE process as the ES-process samples show a lower friction coefficient comparing to those fabricated by DE process at the same conditions of loads and wear frequencies. With the increase of normal loads and reciprocating frequencies, the wear mechanism change from mild wear (adhesion, abrasion and oxidation) to severe wear (delamination, plastic deformation and melting). Therefore, the extrusion ways have significant influences on the wear behaviors of the samples and that the wear resistance of AZ31 magnesium alloy can be improved by extrusion-shear.     

Improvement in the corrosion-erosion resistance of 304 stainless steel with alloyed yttrium

It has been previously demonstrated that yttrium can improve the resistance of stainless steel to sliding wear in corrosive environment. However, the mechanism responsible for the beneficial effect of yttrium on corrosive wear is not well understood. In this work, the erosion behavior of Y-free and Y-containing 304 stainless steel in a dilute H₂SO₄ slurry containing silica sand was investigated, with the aim of exploring the role that yttrium plays. The failure and self-healing of passive films on Y-free and Y-containing 304 stainless steel samples under combined attack by corrosion and mechanical scratch were studied, using an electrochemical scratch technique. The failure of the passive films during dry scratch and identation was also investigated using a micro-mechanical probe with in situ monitoring changes in the electrical contact resistance. In addition, effect of yttrium on electron work function was investigated. All the results demonstrated that yttrium effectively improved properties of the passive film, including corrosion resistance, mechanical behavior and the film stability, resulting in enhanced resistance to corrosion-erosion.     

TiCp/ZA-12复合材料磨损行为的研究

采用XD^TM与搅拌铸造技术相结合的工艺制备TiCp/ZA-12复合材料。利用MM－200摩擦磨损测试仪测试干摩擦条件下这种复合材料的磨损性能。研究了TiC颗粒含量、应用载荷和滑动距离对其磨损程度的影响。结果表明：复合材料的磨损率低于基体合金磨损率，且磨损率随TiC颗粒含量的增加而减小；增大应用载荷和滑动距离，并且复合材料和基体ZA－12合金的磨损程度均增加，但复合材料的增幅明显偏小。同时发现，在磨损过程中存在瞬变载荷，当应用载荷低于瞬变载荷时，磨损表现为微磨损，当高于瞬变载荷时为剧烈磨损，复合材料的瞬变载荷比基体合金高得多。最后分析了复合材料和基体合金的磨面形貌。     

Effect of Microstructure on the Wear Behaviour of a Dual Phase Steel

In this study wear behaviour of 0.1% C containing dual phase steels with three different microstructures have been examined. Intercritical annealing, step quenching and intermediate quenching heat treatments have been applied to the alloy in order to obtain different morphologies of ferrite and martensite. It has been observed that, intercritical annealing lead to highest strength but lowest wear resistance in this alloy. Step quenching suggested to have no beneficial effect on tensile properties but increased the wear resistance. Intermediate quenching was found to be the best heat‐treatment condition. The fibrous microstructure lead to the optimum tensile strength, ductility and wear resistance in this alloy.     

电弧喷涂Al,Zn涂层和Al-Zn伪合金涂层的磨损性能

采用电弧喷涂制备了Al涂层、Zn涂层和Al-Zn伪合金涂层,在Falex试验机上测试了3种涂层的磨损性能。利用扫措电镜（SEM）、X－射线衍射分析（XRD）、能谱分析（EDX）等手段,地试样磨痕形貌及悄进行了分析。结果表明：Al涂层的磨损主要为粘着磨损和磨粒磨损,Zn涂层的磨损主要为氧化磨损,Al-Zn伪合金涂层的磨损兼有Al,Zn2种涂层磨损特征,但更接近于Zn涂层的磨损机理。3种电弧喷涂层中,Zn涂层的耐磨性能优于其他2种涂层,Al-Zn伪合金涂层的耐磨性能介于两者之间,但更接近于Zn涂层。在140℃以下,温度对3种涂层的磨损性能影响不显著。     

高速车轮钢表面激光熔覆铁基合金涂层的摩擦磨损性能

为了探究激光熔覆对高速车轮钢合金涂层摩擦与磨损性能的影响,利用LDM2500-60型半导体全固态激光器在高速车轮钢表面激光熔覆制备Fe基合金涂层。分别采用金相显微镜、能量色散X射线光谱仪、X射线衍射仪(XRD)分析了熔覆涂层的组织结构、元素分布以及物相,利用MM-2000高速摩擦试验机研究了高速车轮材料激光熔覆处理前后轮轨材料的摩擦磨损性能。结果表明:激光熔覆处理能有效改善车轮材料的抗磨损性能,熔覆涂层主要由γ-Fe、Cr7C3碳化物以及含铁固溶体等物相组成,涂层组织主要以树枝晶和共晶为主;车轮合金涂层的磨损速率相比基体材料降低了51%左右,车轮熔覆铁基合金后的轮轨磨损机制主要表现为轻微的磨粒磨损和氧化磨损。     

WC和Nb对氩弧熔覆Ni60+WC+Nb合金层组织和耐磨性的影响

采用氩弧熔覆工艺在4Cr13钢上分别熔覆Ni60、Ni60+WC和Ni60+WC+Nb系合金。比较各种材料熔覆层的显微组织、显微硬度和耐磨性。结果表明,材料的表面硬度和耐磨性等都随WC含量的增加得到很大地提高,而Nb含量的增加对硬度和耐磨性的影响不明显。     

Effects of yttrium and cerium additives in lubricants on corrosive wear of stainless steel 304 and Al alloy 6061

Effects of oxygen active elements, yttrium and cerium, as additives in commercial lubricants on corrosive wear were investigated. Sliding wear losses of stainless steel 304 and Al alloy 6061 lubricated by oil and thin grease respectively with and without yttrium or cerium additive in a corrosive environment were determined. Dilute H₂SO₄ solution (10% H₂SO₄) was used as the corrosive medium and added to the lubricants for the corrosive wear test. The wear test was performed on a pin-on-disc tribometer with the capability of measuring wear in lubricant. The disc was coiled with a copper tube, through which cooling water could pass, so that the wear losses respectively under cooling condition and non-cooling condition could be determined. The results showed that wear losses of the tested materials caused by synergistic attack of wear and corrosion can be effectively reduced by adding small amounts of yttrium or cerium to the lubricant. In addition, the effect of the additives was found more distinctive under the non-cooling condition. Worn surfaces were examined using SEM to clarify the wear mode and thus the wear mechanism.     

医用钴合金表面改性技术的研究进展

钴合金具有优异的生物力学特性、耐磨损性能和耐腐蚀性能,在医学植入领域有着广阔的应用前景,其表面改性技术已成为医用金属材料的研究热点和重点。本文简述了钴合金材料表面改性技术的优势,包括钴合金材料的生物力学特性、耐磨性能、耐腐蚀性能等。同时归纳了钴合金材料因人体体液腐蚀和摩擦磨损会释放出Co、Cr等金属离子而导致生物致敏等问题。在上述基础上,重点综述了近年来钴合金表面改性技术的研究进展,包括离子注入技术、选区激光熔化技术、真空沉积技术。其中,离子注入技术主要包括氮离子注入、钇离子注入、镧离子注入和钛镍离子注入等;选区激光熔化技术主要包括粉层厚度、激光功率、组分含量、扫描方式和扫描速度等;真空沉积技术主要包括物理气相沉积和化学气相沉积。针对不同钴合金表面改性技术,分别从钴合金材料的生物力学特性、耐磨性、耐腐蚀性和生物相容性等方面进行了归纳分析。最后分析了钴合金表面改性的发展趋势,认为钴合金表面改性技术应朝着高生物相容性、无金属离子释放、生物功能化、高耐腐蚀性和高耐磨性的方向发展。     

Ni-Co/纳米ZrO_2复合材料的电化学行为及摩擦磨损性能

通过超声辅助电沉积的方法,在加入粒径为50nm的ZrO_2粉体的氨基磺酸盐镀液中制备了Ni-Co/纳米ZrO_2复合镀层。利用电化学方法(线性扫描伏安法、循环伏安法)对沉积动力学进行分析。通过XRD,SEM和EDS分别对复合镀层的微观结构、表面形貌和相组成等进行表征。同时,对镀层进行了纳米压痕测试和旋转摩擦测试。结果表明,Co~(2+)的电沉积行为遵循3D"成核/生长"机制,合金共沉积电位为-0.72V,复合共沉积电位为-0.70V。ZrO_2纳米粒子的加入降低了体系的极化度,使得电极过程更容易进行。纳米ZrO_2的添加量为15g/L时,镀层硬度、弹性模量以及硬模比分别为6.13GPa,291GPa和0.026;摩擦因数为0.3273,磨损量为0.55×10~(-5)g/m,分别为Ni/Co合金的3/4和1/2,超声和纳米粒子的协同作用能够明显改善镀层的力学性能。