含氮硼酸酯对轧制铝板摩擦学性能及表面质量的影响

目的探讨含氮硼酸脂的摩擦学性能及轧制润滑性能。方法合成一种新型含氮硼酸酯挤压抗磨添加剂(NB)。将合成的含氮硼酸酯分别和磷酸三甲苯酯、磷酸三丁酯进行复配后加入铝材轧制基础油中,配制成多种铝材轧制润滑油。利用四球摩擦磨损试验机考察多种铝材轧制润滑油摩擦学性能,利用轧制实验考察其轧制润滑性能,利用扫描电子显微镜观察轧后表面形貌。对多组样品的磨斑直径、摩擦系数、最大无卡咬负荷、轧制压力、轧制摩擦系数、最小可轧厚度和轧后表面质量进行对比,探究含氮硼酸酯复配比例对铝材轧制润滑油摩擦学性能和轧制润滑性能的影响。结果当含氮硼酸酯和磷酸三甲苯酯、磷酸三丁酯的复配系数为0.5和0.25时,样品的摩擦系数分别降低了35.2%和18.4%,磨斑直径分别降低了48.4%和19%,表现出比单体添加剂更好的抗磨减摩效果。轧制实验也表明,添加含氮硼酸酯后,实验轧制压力降低到了164 MPa和160 MPa,轧制摩擦系数降低到了0.076和0.078,最小可轧厚度分别减少了23%和21%。轧后铝板表面平整,犁沟深浅均一,表面质量好。结论铝材轧制基础油中加入含氮硼酸酯后,改善了摩擦学性能和轧制润滑性能。含氮硼酸酯分别与磷酸三甲苯酯、磷酸三丁酯复配后具有良好的协同效应,轧件表面质量好。     

基于分子动力学理论制备含氮磷硼酸酯添加剂及其摩擦学性能

利用分子动力学(MD)理论设计合成了一种新型含氮磷硼酸酯极压抗磨添加剂NBPE,分别采用元素分析仪和红外光谱仪(FTIR)对分子结构进行表征。采用热重分析法(TG)和饱和蒸汽法分别考察化合物的热稳定性与水解稳定性;采用四球摩擦磨损试验机考察NBPE的含量对润滑油摩擦学性能的影响;利用立式万能摩擦磨损试验机研究不同润滑条件下钢-铜摩擦副的摩擦磨损性能;利用扫描电子显微镜(SEM)观察试样表面磨痕形貌,利用能谱分析仪(EDS)分析磨斑表面附着物组成。结果表明:NBPE是一种具有良好热稳定性、水解稳定性和优异的极压、抗磨性的润滑油添加剂;添加剂在金属表面发生摩擦化学反应形成摩擦化学产物是提高其极压、抗磨性能的根本原因;当润滑油中NBPE的含量为0.15%(质量分数)时,润滑油具有最佳的极压、抗磨性能,其油膜强度提高了148%,磨斑直径降低了23.2%;在钢-铜摩擦过程中,摩擦因数和铜磨损率分别降低了59.4%和45.2%,获得光洁度较好的铜表面。     

新型氮磷添加剂对铜箔轧制摩擦学性能与磨损行为的影响

采用四球摩擦磨损试验机分别考察新型磷系与含氮硼酸酯极压抗磨剂以不同质量分数复配后在铜箔轧制油中的摩擦学特征,利用扫描电子显微镜(SEM)观察磨斑表面形貌,利用能谱分析仪(EDS)分析磨斑表面附着物的组成,并通过冷轧实验研究铜箔轧制摩擦磨损与润滑性能的关系。基于表征润滑性能的最大无卡咬负荷、摩擦因数和磨斑直径3个参数,提出了分析润滑剂摩擦学性能新指标——极压抗磨润滑系数?。结果表明:新型氮磷添加剂在金属表面发生摩擦化学反应形成摩擦化学产物是提高其抗磨减摩性能的根本原因。铜箔与轧辊之间的磨损机制有黏着、犁削和剥离等形式,其中黏着磨损起主导作用;?代替四球测试的结果能较好地解决轧制过程的摩擦磨损问题。     

TiN/BN与AlN/BN纳米混合添加剂的摩擦学性能研究

目的探究TiN/BN与AlN/BN两类纳米混合添加剂在油润滑中的摩擦学性能,分析纳米润滑油润滑机理。方法以油酸作为分散剂,提高纳米添加剂在基础油中的分散性能,利用MRS-10A型四球摩擦磨损实验机对不同混合比例、不同添加浓度的TiN/BN与AlN/BN纳米润滑油进行摩擦学性能测试,使用扫描电镜观察磨斑表面形貌,用EDS和XPS检测磨斑表面元素种类及相应化合价态。结果经油酸分散的混合纳米粒子的质量比为1︰1时,纳米润滑油表现出最好的抗磨减摩性能。其中TiN/BN纳米混合添加剂的质量分数为0.6%时,磨斑直径和摩擦系数较基础油分别降低34.97%和16.75%,最大无卡咬负荷提高65.96%;AlN/BN纳米混合添加剂的质量分数为0.2%时,磨斑直径和摩擦系数较基础油分别降低24.49%和11.76%,最大无卡咬负荷提高38.30%。磨斑表面磨痕沟槽深度、宽度减小,表面粗糙度明显降低。结论分散在油液中的AlN、BN、TiN纳米粒子进入摩擦副间发挥承载支撑作用,将滑动摩擦变为滑动-滚动混合摩擦,降低摩擦磨损。进入摩擦副间的AlN纳米粒子由于高表面能特性,沉淀吸附于摩擦表面凹坑处,修复磨损表面,TiN、BN纳米粒子与摩擦表面发生化学反应,生成由Fe-O、Ti-O、BO_x及TiN_xO_y等物质所构成的自修复膜,表现出较好的抗磨减摩及自修复性能。     

离子液体和ZDDP添加剂的减摩抗磨性及成膜机理探讨

目的顺应当前尽可能选用低黏度润滑油而满足节能减排的要求,进一步探讨离子液体作添加剂时的摩擦润滑机理。方法选用低黏度的聚α烯烃(PAO-4和PAO-8)为基础油,以二烷基二硫代磷酸锌(ZDDP)和季膦盐油酸离子液体(IL)为添加剂,在四球试验机上分别测量了40、100℃下的摩擦系数,并对比磨斑直径,对磨损表面进行SEM和EDS分析。利用轮廓仪对磨斑表面进行三维扫描,并分析其表面粗糙度。结果与基础油对比,离子液体有效降低了摩擦系数,而传统添加剂ZDDP则导致摩擦系数上升。在部分工况,尤其是高温环境下,离子液体和ZDDP均可有效降低磨损。EDS和表面粗糙度结果可推断:ZDDP和IL在摩擦表面产生了两种截然不同的摩擦反应膜。结论离子液体可以明显改善基础油的摩擦学性能。ZDDP和IL产生的不同摩擦膜引起了摩擦性能的不同,二者的成膜机理值得进一步探讨。     

非硫磷有机钼的摩擦学性能研究

目的 研究非硫磷有机钼的摩擦学性能,以满足发动机润滑油低黏度化发展的需求。方法 实验室合成了一种新型不含硫磷元素的油溶性有机钼添加剂（SPFMo）,并将其按照不同质量分数添加到0W20润滑油中,利用四球摩擦磨损试验机,详细分析了不同SPFMo添加量、温度、载荷和速度对SPFMo在0W20中摩擦学性能的影响,并采用3D激光共聚焦显微镜和扫描电子显微镜对磨痕形貌和成分进行分析。 结果 SPFMo具有优异的减摩抗磨性能,可以使0W20的摩擦系数和磨斑直径均减小,摩擦过程中Mo元素会发生富集,生成包含MoS2、MoO3等物质的摩擦化学反应膜,从而实现减摩、抗磨和自修复。确定了SPFMo在0W20中可以发挥良好摩擦学性能的添加量和使用温度区间分别为0.25%~0.5%和100~130 ℃,120 ℃时,0.5%SPFMo能够使0W20润滑油的COF降低27.5%,磨斑直径降低7.8%。0W20+0.5%SPFMo润滑油的COF,随着温度的升高先减小后增大,随着转速的增大而减小,随着载荷的增大而增大;0W20+0.5%SPFMo润滑油的磨斑直径,随着温度的升高先减小后增大,随着转速和载荷的增大而增大。结论 SPFMo的添加可有效提高润滑油的摩擦学性能,研究结果可为新型发动机低黏油润滑添加剂的设计和选择提供参考。     

氧化石墨烯和二烷基二硫代磷酸锌添加剂对基础油PAO10摩擦学性能的影响

目的 探究氧化石墨烯(GO)和二烷基二硫代磷酸锌(ZDDP)添加剂的摩擦学性能以及协同作用机理。方法 选用GO和ZDDP作添加剂,利用纳米粒度分析仪、傅里叶变换红外光谱仪(FTIR)和原子力显微镜(AFM)分别对GO的粒径、表面官能团和层数进行表征。在四球摩擦试验机上对GO的摩擦磨损性能进行初步研究,并考察了ZDDP添加剂以及ZDDP和GO混合添加剂对基础油摩擦磨损性能的影响。利用金相显微镜、扫描电子显微镜(SEM)和能谱仪对钢球磨斑直径、磨斑形貌和磨斑表面的元素进行分析。利用球–盘点接触光干涉油膜厚度测量试验台,研究了GO和ZDDP在乏油条件下对基础油成膜特性的影响。结果 GO表现出了良好的减摩抗磨性能,在0.03%时减摩抗磨效果最佳,与基础油相比,摩擦因数降低了31.9%,磨斑直径减小了约20.1%;当ZDDP质量分数为2.5%时,油样的摩擦因数约为0.067,磨斑直径约为407 μm,与PAO10纯基础油相比,分别降低了约18.5%和41.86%;当ZDDP和GO的质量分数分别为2.5%和0.01%时,油样的减摩性能得到了有效提高,摩擦因数约为0.056,与仅添加ZDDP的油样相比,摩擦因数降低了约16.7%;当卷吸速度为90 mm/s和180 mm/s时,单独添加ZDDP或添加ZDDP和GO均可有效减缓接触区内的乏油状态,提高基础油的中心膜厚。结论 GO添加剂具有优异的减摩抗磨性能。GO和ZDDP作为复配添加剂有效地减缓了摩擦对偶间的摩擦磨损,表现出了较好的协同作用。在乏油条件下,在PAO10基础油中添加GO、ZDDP以及ZDDP和GO复配添加剂时,均可不同程度地减缓接触区内的乏油状况。     

磷基无卤素油溶性离子液体润滑添加剂的摩擦学特性

以磷酸二异辛酯(EDHPA)作为阴离子,双季磷盐为阳离子合成一种新型的无卤素离子液体并作为 PAO 10 的润滑添加剂与市售 T306 做比较。 通过 SRV-Ⅴ摩擦磨损试验机考察其摩擦学性能,通过扫描电子显微镜对磨损形貌进行表征,通过非接触式三维轮廓仪对磨损体积进行测量,通过 ECR 对摩擦过程中摩擦膜变化进行分析,通过 XPS 元素分析对磨斑表面化学元素和变化进行分析。 结果表明合成的新型无卤素离子液体作为 PAO 10 的添加剂时具有优异的摩擦学性能,同时极大程度的提高了 PAO 10 的极压承载能力。 新型离子液体在摩擦过程中发生摩擦化学反应,其中较长的烷基链与极性元素 P 在摩擦时生成致密且厚的边界润滑膜,提高了 PAO 10 体系的减摩抗磨性能和极压承载性能。     

非晶合金粉末作为润滑油添加剂的摩擦学性能

采用水雾化法制备得到了超细Mn55Fe25P10B7C3非晶合金粉末,将其作为润滑油添加剂以不同含量加入到PAO6基础油中,利用四球摩擦实验系统评估了粉末添加前后润滑油的摩擦系数、对磨球的磨斑尺寸、表面形貌和表面粗糙度等,从而对比获得了该类非晶合金粉末添加对PAO6基础油摩擦学性能的影响.结果表明,水雾化合金粉末的颗粒...     

有机钼为润滑油抗磨减摩添加剂的摩擦学性能研究

用四球摩擦磨损试验机考察了两种油溶性有机钼(二硫代磷酸氧钼、二硫代磷酸钼)抗磨减摩添加剂在液体石蜡基础油中的摩擦学性能,采用扫描电子显微镜对边界润滑状态下形成的磨斑形貌和表面膜的元素组成进行了分析。试验结果表明:两种有机钼添加剂均具有优异的抗磨减摩性能和极好的承载能力。其中二硫代磷酸钼添加剂使基础油的抗磨性能提高53 %,减摩性能提高40 %,极压承载能力提高一倍多。SEM分析显示钢球表面的磨痕和犁沟较浅,且有含硫和钼的沉积物生成。由此推断出有机钼添加剂在摩擦副表面形成吸附膜,部分吸附膜通过摩擦化学反应生成了具有抗磨减摩作用的MoS2和FeS膜,从而起到了改善摩擦磨损性能的作用。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.