激光熔覆原位自生TiC增强Ni3(Si,Ti)金属间化合物复合涂层研究

运用激光熔覆技术在GH864镍基合金表面制备原位自生TiC颗粒,以增强Ni3(Si,Ti)金属间化合物复合涂层.实验结果表明:利用激光表面熔覆技术,可以在镍基合金表面直接原位合成TiC颗粒增强的Ni3(Si,Ti)金属间化合物复合涂层、涂层和基体呈良好的冶金结合,涂层宏观质量完好,无裂纹和气孔等缺陷.涂层组织由γ Ni、Ni3(Si,Ti)、Ni5Si2和TiC组成.涂层的显微硬度可达HV780,是基材显微硬度的2.5倍.     

感应熔敷WC/Ni基复合涂层的组织和性能

采用高频感应熔敷技术，以Ni60A自熔合金粉末、微纳米碳化钨粉末为原料，在16Mn钢表面制备出以微纳米WC颗粒为增强相的Ni基金属陶瓷涂层，并测试了涂层的显微硬度。利用磨擦磨损试验机，以45#钢为对磨偶件，评价了涂层的滑动干磨擦性能。实验结果表明：涂层的硬度为890～910,磨擦系数为0．3-0．4，耐磨性比16Mn钢提高4倍以上。     

激光熔覆原位合成TiC的Ni／TiC复合层显微组织与性能研究

利用5kW CO2激光器和同轴送粉的方法,在Q235钢基材表面原位合成强化相为TiC的Ni／TiC复合材料层。研究了不同Ni相对含量对熔覆层的显微组织形貌和相组成的影响,并进行了耐磨性试验。结果表明,熔覆层的物相构成为Ni和TiC,熔覆层耐磨性随Ni相对含量的减少而增大。     

原位合成TiC颗粒增强铝基复合材料及其磨损性能

利用原位合成的方法在几种锻铝基体中合成了TiC颗粒.X射线衍射谱表明,在复合材料的显微组织中TiC是惟一反应生成物.与基体材料相比,引入TiC后材料的耐磨性能有很大幅度的提高,且磨损性能与基体材料的强度之间没有必然的联系.对磨损试样表面的sEM观察显示,在磨损过程中TiC颗粒凸起于基体,在表面起支撑载荷的作用,同时使摩擦副(滚轮)与基体表面之间形成一个储存润滑油的间隙,从而改善了磨损过程中的润滑条件,减小了试样的磨损量.     

氩弧熔敷原位自生WC复合涂层组织及耐磨性

为提高采煤机中截齿的耐磨性能,利用氩弧熔敷技术,在35CrMnSi钢表面制备WC增强Ni基复合涂层。利用OM、SEM、XRD和EDS分析复合涂层的显微组织,采用显微维氏硬度仪测试复合涂层的显微硬度,并测试涂层在室温磨损条件下的耐磨性能。结果表明：氩弧熔敷涂层组织均匀致密,熔敷涂层与基体呈冶金结合,主要由WC、W：C、T—Ni、（Fe,Cr）23,C6等物相组成;WC颗粒呈弥散分布,颗粒尺寸为1txm;熔敷涂层可以改善基体的表面硬度,最高显微硬度可达12．6GPa;熔敷涂层在室温冲击磨粒磨损实验条件下,具有优异的耐磨性,磨损机制主要是磨粒磨桶．其耐磨性较35CrMnSi基体提高近12倍。     

TiC颗粒增强2618复合材料的研究

用原位反应合成法(即XD法)制备了TiC颗粒增强2618复合材料,并用X-ray衍射分析技术、透射电镜及拉伸实验对其结构和性能进行了研究.结果表明利用原位反应合成法可以制备TiC增强多元素合金2618为基体的复合材料;与普通熔铸法相比,逆向熔铸法可以缩短熔铸时间,减少TiC粒子损失,从而制得较为理想的复合材料;TiC粒子的加入可以提高2618合金的力学性能.图6,表1,参8.     

原位生成TiC/Al基复合材料的制备

采用原位法（ＸＤ法）成功地制备了ＴｉＣ／Ａｌ基复合材料,并通过ｘ－射线衍射仪及显微镜研究了自生增强体ＴｉＣ颗粒在α－Ａｌ基体中的浸润情况。结果表明：原位生成ＴｉＣ／Ａｌ基复合材料中自生增强体ＴｉＣ在基体中浸润良好,加入Ｍｇ后可使ＴｉＣ颗粒溶入的数目增多,且使其弥散细小均布于α－Ａｌ基体中（ＴｉＣ颗粒直径为（０．１～１０．０）μｍ）,晶界上无明显的偏聚。     

A1/TiC复合材料铸造流动性的研究

通过实验研究了基体Al合金和TiC颗粒含量不同的四种Al／TiC复合材料的流动性．并根据流动性的差异,提出了不同的铸造工艺成型方法．     

原位合成TiC/Ni40钢结硬质合金组织与性能研究

以钛铁粉、铬铁粉、铁粉、镍粉和胶体石墨等为原料,原位合成了TiC/自熔合金Ni40钢结硬质合金,并用扫描电镜(SEM)、X射线衍射仪和洛氏硬度计等对所制备的试样进行了组织结构和硬度分析.研究结果表明所合成的钢结硬质合金主要相组成为TiC和Fe-Cr-Ni固熔体,所合成的硬质相TiC颗粒细小,随烧结温度升高TiC颗粒略有长大.原位合成TiC/Ni40钢结硬质合金的密度和硬度则因烧结温度和硬质相TiC的含量不同而有所不同.原位合成TiC/Ni40钢结硬质合金的密度在5.35～5.96×103 kg/m3之间,硬度在HRC58.5～70.5之间.     

自生TiCP/Ti-6Al复合材料中TiC铸态形貌的形成机制

采用反应自生法制备了 Ti CP增强钛合金基复合材料 ,并通过 XRD、SEM对复合材料的相组成、微观组织进行了仔细的分析 .结果表明 :Ti- 6Al- 1 .8C合金中 Ti C的形态有树枝状晶和短棒状两种形态 .在对 Ti C形成机制的分析中认为 ,树枝状 Ti C是包晶反应之前过冷熔体中 ,以连续生长方式自由生长而成的初生 Ti C,而短棒状 Ti C则是包晶反应后在β- Ti的内部生核并长大而成 .     

原位生成TaB_2颗粒增强镍基复合涂层的组织与耐磨性

以Ta粉、B粉和Ni60A粉为原料,利用氩弧熔覆技术在Q235钢基体表面制备原位生成TaB_2颗粒以增强Ni基复合涂层。通过金相显微镜、扫描电镜、X射线衍射仪、显微硬度计以及摩擦磨损试验机对复合涂层的显微组织、物相、显微硬度以及涂层耐磨性进行分析研究。结果表明,镍基复合涂层形成良好,没有气孔和裂纹等缺陷,涂层与基体呈现良好的冶金结合。熔覆层由原位生成的TaB_2颗粒相、Fe-Cr相及Cr_7C_3相组成。TaB_2颗粒弥散分布在基体上,氩弧熔覆涂层的平均显微硬度达到11.50 GPa,比基体Q235钢提高约4倍。在室温干滑动磨损条件下,该熔覆涂层的耐磨性比基体提高约12倍。     

氩弧熔覆原位合成ZrC-TiB2/Fe基复合涂层组织与耐磨性

为提高钢材料表面性能,以Ti、Zr、B4C和Fe等粉末为原料,采用氩弧熔覆技术,在Q345D钢表面制备出原位合成ZrC和TiB2颗粒增强Fe基复合涂层。利用扫描电镜、X射线衍射仪、显微硬度计和滑动摩擦磨损实验机研究了熔覆层的显微组织、硬度和耐磨性。结果表明:熔覆层组织由方块状ZrC颗粒、长条状TiB2颗粒和α-Fe基体组成;熔覆层与基体呈冶金结合,界面洁净无裂纹、气孔等缺陷;熔覆层平均硬度(HV)为14 GPa;在室温干滑动摩擦磨损实验条件下,其耐磨性约为基体的18倍。该研究为原位合成ZrC和TiB2提供了新方法。     

原位TiC颗粒细化喷射沉积7075铝合金组织的机理

采用原位反应喷射沉积法制备TiCP/7075(TiCP体积分数为2.91%)铝合金,观察其微观组织. 应用Image Tool软件及平均截线法统计平均晶粒尺寸,并与喷射沉积7075铝合金进行对比. 发现前者的晶粒尺寸比后者减小50%左右,表明原位TiC颗粒对喷射沉积7075铝合金组织具有显著的细化作用. 从形核的属性、速度以及过程的晶体学分析对其细化机理进行了解释.     

Microstructure characteristics of Ni/WC composite cladding coatings

A multilayer tungsten carbide particle (WCp)-reinforced Ni-based alloy coating was fabricated on a steel substrate using vacuum cladding technology. The morphology, microstructure, and formation mechanism of the coating were studied and discussed in different zones. The microstructure morphology and phase composition were investigated by scanning electron microscopy, optical microscopy, X-ray diffraction, and energy-dispersive X-ray spectroscopy. In the results, the coating presents a dense and homogeneous microstructure with few pores and is free from cracks. The whole coating shows a multilayer structure, including composite, transition, fusion, and diffusion-affected layers. Metallurgical bonding was achieved between the coating and substrate because of the formation of the fusion and diffusion-affected layers. The Ni-based alloy is mainly composed of γ-Ni solid solution with finely dispersed Cr₇C₃/Cr₂₃C₆, CrB, and Ni+Ni₃Si. WC particles in the composite layer distribute evenly in areas among initial Ni-based alloying particles, forming a special three-dimensional reticular microstructure. The macrohardness of the coating is HRC 55, which is remarkably improved compared to that of the substrate. The microhardness increases gradually from the substrate to the composite zone, whereas the microhardness remains almost unchanged in the transition and composite zones.     

TiC/Fe cermet coating by plasma cladding using asphalt as carbonaceous precursor

A new Ti-Fe-C compound powder for plasma cladding was prepared by heating a mixture powder of ferrotitanium and asphalt pyrolyzed as carbonaceous precursor. The carbon by the pyrolysis of the asphalt acts as a reactive constituent as well as a binder in the compound powder. TiC/Fe cermet coatings were prepared by plasma cladding with the compound powder. Results show that the Ti-Fe-C compound powder has a very tight structure, which can avoid the problem that reactive constituent particles are separated during cladding. The TiC/Fe cermet coating presents a typical morphology of plasma cladding coatings with two different laminated layers: one is the composite layers in which the round fine TiC particles (<500nm) are dispersed within a Fe matrix, the other is the paragentic layers of TiC and Ti₂O₃. The coating shows high hardness and excellent wear resistance. The surface hardness of the coating is 68±5(HR30N). In the same fretting conditions, the wear area of Ni60 coating is about 11 times as much as the TiC/Fe cermet coating.     

TiC/Fe cermet coating by plasma cladding using asphalt as carbonaceous precursor

A new Ti-Fe-C compound powder for plasma cladding was prepared by heating a mixture powder of ferrotitaniurn and asphalt pyro- lyzed as a carbonaceous precursor. The carbon by the pyrolysis of the asphalt acts as a reactive constituent as well as a binder in the compound powder. The TiC/Fe cermet coatings were prepared by plasma cladding with the compound powder. Results show that the Ti-Fe-C compound powder has a very tight structure, which can avoid the problem of the reactive constituent particles being separated during cladding. The TiC/Fe cermet coating presents a typical morphology of plasma cladding coatings with two different laminated layers： one is the composite layer in which the round fine TiC particles （〈500 nm） are dispersed within a Fe matrix, the other is the paragentic layer of TiC and Ti2O3. The coating shows high hardness and excellent wear resistance. The surface hardness of the coating is 68 ± 5（HR30N）. In the same fretting conditions, the wear area of Ni60 coating is about Ⅱ times as much as the TiC/Fe cermet coating.     

TiC强化Cr12MoV基复合材料的组织和性能分析

用原位合成铸造法制备了TiC弥散强化Cr1 2MoV钢基复合材料 ,对材料的制备工艺、力学性能及微观组织进行了系统的研究 .试验结果表明 ,用原位合成铸造法制备TiC颗粒增强钢基复合材料的工艺具有可行性 ,且易于实现工业化生产 .TiC颗粒在基体中分布均匀 ,形状呈块状和球状 ,分布在晶内和晶界上 .颗粒与基体结合良好 ,且无团聚现象 .引入TiC后材料的室温和高温强度比基体材料的强度均有提高 ,说明TiC颗粒起了良好的强化效果 .金属基体与高耐磨性的增强粒子相结合 ,使复合材料获得了优异的耐磨性能 .在提高材料的强度、耐磨性、抗热疲劳性能的同时 ,TiC的加入也使材料的塑性和韧性有一定程度的下降     

反应火焰喷涂TiC/Fe金属陶瓷复合涂层的组织结构

采用钛铁矿粉、石墨粉和铁粉为主要原料,利用反应火焰喷涂技术成功制备了TiC/Fe金属陶瓷复合涂层. 采用X射线衍射仪、扫描电镜、透射电镜等手段,研究了涂层的显微组织结构. 结果表明,反应火焰喷涂TiC/Fe复合涂层主要由TiC和Fe两相组成. 涂层具有多层多相的结构,即由TiC含量不同的片层交替叠加而成;在富TiC片层中,大量的、比较细小的(粒度小于0.5 μm)、大致呈球形的TiC颗粒弥散分布在Fe基体上. 这种显微组织结构有利于改善金属陶瓷涂层的耐磨性能.