铁基合金激光熔覆层的高温磨损性能

 为提高40Cr钢表面耐磨性,采用预置激光熔覆法在40Cr基体表面制备Fe基涂层,利用HT-500摩擦磨损实验机测定干摩擦条件下,基体和熔覆层的摩擦因数随温度变化的规律。利用表面粗糙度轮廓仪测量磨痕的深度和宽度,SEM观察熔覆层以及磨痕的显微组织形貌,使用HV-1000型显微硬度仪检测基体和熔覆层结合部分的硬度。研究结果表明:熔覆层平均显微硬度值达到373.8HV(0.2);显著高于基体硬度198.4HV(0.2)。在干摩擦条件下,随着温度升高,磨损过程逐渐变平缓,平均摩擦因数降低,磨损率增加,耐磨性下降;在350~400 ℃之间,熔覆层磨损性能优于基体。     

铁基合金激光熔覆层高温润滑磨损性能

 为提高40Cr合金钢的表面耐磨性,采用预置激光熔覆法在40Cr基体表面制备铁基合金涂层, 利用扫描电镜观察分析熔覆层显微组织形貌,用显微硬度仪测试熔覆层截面显微硬度,用摩擦磨损试验机测定在润滑条件下基体、熔覆层的摩擦系数随温度变化的规律。研究结果表明:熔覆层与基体实现良好冶金结合,熔覆层横截面微观组织呈现平面晶、树枝晶和胞状晶分布;熔覆层硬度值介于617.5~926.6 HV0.2之间,基体硬度介于205.2~278.2 HV0.2之间;在200 ℃以下,熔覆层摩擦系数在磨程中趋于平稳,在0.1附近轻微波动,小于基体平均摩擦系数;当温度超过200 ℃,油膜分解,引发润滑失效,磨损方式向干摩擦转化,磨损机理从微切削磨损主导向粘着磨损、磨粒磨损和氧化磨损复合磨损方式转化。     

斜齿轮激光熔覆Fe基合金组织与性能研究

采用激光熔覆技术在斜齿轮钢表面制备Fe基熔覆层。通过光学显微镜、显微硬度计对熔覆层进行金相组织与显微硬度分析,采用磨损机对熔覆层和基材进行摩擦实验。结果表明:当激光功率为750W,送粉速率为20g/min,扫描速度10mm/s,离焦量为16.4mm时,铁基熔覆层与基体结合界面有明显的白亮带,激光熔覆效果较好,熔覆层的显微硬度值分布在845.3HV至955.6HV之间,约为基体硬度(419.7HV)2倍;熔覆层摩擦磨损性能得到了提高;熔覆层显微组织为均匀而细小的铁素体和珠光体,力学性能优于基体材质。     

激光熔覆TiC陶瓷涂层的组织和摩擦磨损性能研究

采用激光熔覆技术在TC4合金表面上制备了TiC陶瓷涂层,分析了熔覆层的微观组织,测试了熔覆层的硬度和摩擦磨损性能。结果表明:TiC激光熔覆层分为熔覆区和稀释区两个区域,熔覆区未受到基底的稀释,由TiC颗粒和TiC树枝晶组成;稀释区受到了基底的稀释,由TiC树枝晶和钛合金组成;TiC激光熔覆层的显微硬度在HV700~1500之间,明显地改善了TC4合金表面的摩擦和磨损性能。     

稀土CeO_2对镍基纳米Al_2O_3激光熔覆复合涂层组织和性能的影响

采用激光熔覆技术在45钢基体上制备了不同CeO2含量的镍基纳米Al2O3复合涂层,对熔覆层进行了微观组织分析和显微硬度测试。结果表明,随着CeO2含量的增加,熔覆层组织由亚共晶向共晶组织转变;加入1.0%CeO2对镍基纳米Al2O3熔覆层的组织起到明显的细化和净化作用,枝晶生长的方向性减弱,组织趋向均匀,熔覆涂层的显微硬度值比未加稀土的涂层提高了60-95HV0.2。     

激光工艺参数对钛合金表面NiCrBSi合金熔覆层组织及硬度的影响

在TC4合金表面进行了激光熔覆NiCrBSi合金涂层的试验 ,利用SEM和XRD等对熔覆层的微观组织进行了分析 ,测试了熔覆层的显微硬度。结果表明 ,激光工艺参数对熔覆层的组织和硬度有极大的影响 ,随稀释率的增加 ,激光熔覆层中形成了TiB2 和TiC等颗粒增强相 ,熔覆层的硬度明显提高。     

钛合金表面激光熔覆TiC_p/Ni基合金复合耐磨涂层

采用激光熔覆技术在TC4合金表面制备TiC颗粒增强的Ni基合金复合材料涂层,测试了熔覆层的硬度和滑动摩擦磨损性能,分析了熔覆层的强化机制。结果表明,熔覆层中存在颗粒强化、固溶强化和细晶强化等多种强化作用,熔覆层的显微硬度达HV900～1100,耐磨性能比TC4合金显著提高。     

磁场辅助激光熔覆制备Ni60CuMoW复合涂层

采用磁场辅助激光熔覆技术,在Q235钢表面制备了Ni60CuMoW复合涂层,借助SEM,EDS 和XRD 等表征手段对涂层进行了微观组织和物相分析,利用维氏硬度计测试了复合涂层截面的显微硬度分布,通过摩擦磨损实验和电化学测试系统研究了复合涂层的磨损性能和耐腐蚀性能。研究结果表明:涂层主要由-Ni,Cu）固溶体、硅化物和硼化物组成,Cr3Si晶粒细化且均匀致密;磁场辅助作用下,激光熔覆涂层平均显微硬度达到913HV0.5,为无磁场辅助涂层的1.5 倍,磨损失重仅为无磁场涂层的36%,自腐蚀电位上升了100 mV,腐蚀电流密度降低了70%,耐磨耐蚀性能得到了显著改善。     

激光、激光技术 激光应用 激光工业应用

TG156.99 2006032065激光熔覆TiC陶瓷涂层的组织和摩擦磨损性能研究=Mi-crostructure and friction wear properties of TiC laser cladlayer[刊,中]/孙荣禄(天津工业大学机械电子学院.天津(300160)) ,杨贤金∥光学技术.—2006 ,32(2) .—287-289采用激光熔覆技术在TC4合金表面上制备了TiC陶瓷涂层,分析了熔覆层的微观组织,测试了熔覆层的硬度和摩擦磨损性能。结果表明,TiC激光熔覆层分为熔覆区和稀释区两个区域,熔覆区未受到基底的稀释,由TiC颗粒和TiC树枝晶组成;稀释区受到了基底的稀释,由TiC树枝晶和钛合金组成;TiC激光熔覆层的…     

激光熔覆TiC-Ni复合涂层的摩擦磨损性能和磨损机制研究

利用光学显微镜和扫描电镜观察了钛合金表面TiC-Ni激光熔覆层的宏观形貌和微观组织,测试了激光熔覆层的硬度、摩擦系数和磨损量。利用SEM观察了磨损的表面形貌和磨屑的形貌,分析了激光熔覆层的磨损机制。结果表明:激光熔覆层组织致密,无气孔和裂纹,硬度为基材的3倍;激光熔覆层的摩擦系数随环境压力的降低而提高,磨损量随环境压力的降低、法向载荷的增加而增加;低载时为轻微的磨粒磨损,高载时为严重的剥层磨损。     

Al、Nd对Cr12MoV钢表面镍基熔覆层的组织及性能影响

为了解决Cr₁₂MoV钢溶蚀、表面碎裂等问题,利用Al-Ni、Nd-Ni粉末在Cr₁₂MoV钢上进行激光熔覆实验,研究了Al、Nd对镍基覆层的宏微观形貌、组织及表面性能的影响。结果表明:Al可以减少熔覆层裂纹的产生,同时降低覆层硬度,使熔覆层中产生具有减磨作用的硬质相Al₂O₃等,降低覆层磨损量,14%Al覆层磨损量比2%Al的覆层磨损量低44.5%,Al较优质量分数为14%;Nd的晶粒细化作用明显,显著提升覆层显微硬度,2.5%Nd覆层平均硬度比基体平均硬度高36.8%,Nd较优质量分数为2.5%。     

Wear properties of compact graphite cast iron with bionic units processed by deep laser cladding WC

By simulating the cuticles of some soil animals, the wear resistance of compact graphite cast iron (CGI) processed by laser remelting gets a conspicuous improvement. In order to get a further anti-wear enhancement of CGI, a new method of deep laser cladding was used to process bionic units. By preplacing grooves then filling with WC powders and laser cladding, the bionic units had a larger dimension in depth and higher microhardness. Fe powder with different proportions from 30% (wt.) to 60% (wt.) was added into WC before laser processing for a good incorporation with CGI substrate. The improved laser cladding units turned out to induce higher wear resistance in comparison with laser remelting ones. The depth of the layer reached up to 1 mm. The results of dry sliding wear tests indicated that the specimen processed by laser cladding has a remarkable improvement than the ones processed by laser remelting. It should be noted that the wear mass loss was essentially dependent on the increase in WC proportion.     

Microstructure and interface interaction in laser induction hybrid cladding of Ni-based coating

Based on the powder feeding laser induction hybrid cladding experiments by means of three different laser and induction energy, the microstructure of Ni-based coating and interface characteristics between the Ni-based coating and steel substrate were investigated. The results show that the hybrid cladding energy including laser and induction energy has an important influence on the formation of the interface and the microstructure of the Ni-based coating characterized by the dendrite. In addition, the laser and induction energy can complement each other. For high hybrid cladding energy, the single phase Fe-Ni-Cr solid solution is formed at the interface between the coating and substrate, while the microhardness of the Ni-based coating decreases. For low hybrid cladding energy, the solid solution phases of Fe-Ni-Cr and Ni-Fe-Cr are respectively obtained on both sides of the interface and microhardness of the Ni-based coating is relatively high. During laser induction hybrid cladding, the metallurgical bond characterized by the white light layer is achieved between the coating and substrate, and the extent of metallurgical reaction can be controlled by adjusting the laser energy and induction energy appropriately.     

Effect of pulsed laser parameters on in-situ TiC synthesis in laser surface treatment

Commercial titanium sheets pre-coated with 300-μm thick graphite layer were treated by employing a pulsed Nd:YAG laser in order to enhance surface properties such as wear and erosion resistance. Laser in-situ alloying method produced a composite layer by melting the titanium substrate and dissolution of graphite in the melt pool. Correlations between pulsed laser parameters, microstructure and microhardness of the synthesized composite coatings were investigated. Effects of pulse duration and overlapping factor on the microstructure and hardness of the alloyed layer were deduced from Vickers micro-indentation tests, XRD, SEM and metallographic analyses of cross sections of the generated layer. Results show that the composite cladding layer was constituted with TiC intermetallic phase between the titanium matrix in particle and dendrite forms. The dendritic morphology of composite layer was changed to cellular grain structure by increasing laser pulse duration and irradiated energy. High values of the measured hardness indicate that deposited titanium carbide increases in the conditions with more pulse duration and low process speed. This occurs due to more dissolution of carbon into liquid Ti by heat input increasing and positive influence of the Marangoni flow in the melted zone.     

Microstructure and wear properties of TiCN/Ti coatings on titanium alloy by laser cladding

Titanium carbide nitride (TiCN) reinforced Ti coating was fabricated on the surface of Ti–6Al–4V alloy by laser cladding method. Microstructure and wear properties at the surface of the coating in atmosphere were investigated. Three zones can be distinguished of the coating: the clad zone (CZ), the heat affected zone (HAZ) and the substrate. The clad zone is composed of TiCN dendrites, TiO₂ and Ti. A metallurgical bonding between the coating and the substrate was obtained. The microhardness and wear resistance of the TiCN/Ti coating are significantly improved. The average hardness of the coating is about 3 to 6 times of that of the substrate. The friction coefficients of the substrate and the coating are 0.48 and 0.34 respectively. The friction coefficient of the Ti–6Al–4V substrate was insensitive to the normal load, while that of the cladded TiCN/Ti coating was very sensitive to the normal load. The wear mass losses of the cladded samples are much lower than that of the substrate whatever the normal load is.