接触线用微合金化Cu—Ag—Cr合金时效析出行为和电磨损机理探讨

对真空熔炼制得的微合金化Cu-0．1Ag-0．6Cr合金进行固溶、时效处理后的显微硬度和导电率进行了测试，并利用TEM、SEM对合金析出相和电滑动磨损表面形貌进行了观察和分析。结果表明形变和时效综合作用能显著提高合金的综合性能：该合金经980℃×20min固溶处理、60％变形后，在480℃时效30min可获得良好综合性能，其显微硬度和电导率分别可达165Hv和83％IACS；而固溶后直接时效仅为154HV和78％IACS。在载流条件下，合金的磨损量随加载电流的增加而增大；磨损过程中，粘着磨损、磨粒磨损和电烧蚀磨损等形式交互作用，促进了磨损过程的进行。     

Cu-Cr-Zr-Ce-Y合金时效析出特性和受电磨损行为研究

对Cu-Cr-Zr—Ce—Y合金时效析出特性、受电滑动磨损形貌及电磨损机理进行研究。结果表明：Cu-0．34Cr-0．06Zr-0．03Ce-0．03Y合金在950℃固溶1h后,在480℃时效处理能获得较高的显微硬度和导电率。时效前冷变形能大大加快析出相的析出,析出相对位错的钉扎作用强烈阻碍合金再结晶的形核和长大,使合金产生明显的时效硬化。固溶合金经60％冷变形后在480℃时效2h,其显微硬度和导电率分别高达163HV和79．78％IACS,而固溶后直接时效时仅为119HV和68．25％IACS。受电磨损时,合金的磨损量随加载电流的提高而增加,其主要磨损机制为粘着磨损、磨粒磨损及电蚀磨损。     

接触线用Cu-Ag-Zr-Ce合金的电滑动磨损性能

采用真空感应熔炼炉制备Cu-Ag、Cu-Ag-Zr以及Cu-Ag-Zr-Ce合金,利用自制且能模拟接触线实际运行工况的载流磨损试验机对各不同合金线材的电滑动磨损性能进行研究,并借助扫描电镜对磨损前后Cu-Ag-Zr-Ce合金的组织形貌进行分析。结果表明:Cu-Ag-Zr-Ce线材的磨损率随着加载电流和滑行距离的增大而增大;粘着磨损、磨粒磨损和电侵蚀磨损是Cu-Ag-Zr-Ce线材电滑动磨损的主要机制。在同种实验条件下,Cu-Ag-Zr-Ce线材的耐磨性能优于Cu-Ag-Zr和Cu-Ag合金的耐磨性能,相同实验条件下Cu-Ag合金的磨损率为Cu-Ag-Zr-Ce和Cu-Ag-Zr合金磨损率的2~4倍。     

Influence of graphite content on sliding wear characteristics of CNTs-Ag-G electrical contact materials

CNTs-Ag-G electrical contact composite material was prepared by means of powder metallurgical method. The influence of the graphite content on sliding wear characteristics of electrical contact levels was examined. In experiments, CNTs content was retained as 1% (mass fraction), and graphite was added at content levels of 8%, 10%, 13%, 15% and 18%, respectively. The results indicate that with the increase of graphite content, the contact resistance of electrical contacts is enhanced to a certain level then remains constant. Friction coefficient decreases gradually with the increase of graphite content. Wear mass loss decreases to the minimum value then increases. With the small content of graphite, the adhesive wear is hindered, which leads to the decrease of wear mass loss, while excessive graphite brings much more worn debris, resulting in the increase of mass loss. It is concluded that wear mass loss reaches the minimum value when the graphite mass fraction is about 13%. Compared with conventional Ag-G contact material, the wear mass loss of CNTs-Ag-G composite is much less due to the obvious increase of hardness and electrical conductivity, decline of friction surface temperature and inhibition of adhesive wear between composites and slip rings.     

变形量对接触线用Cu-Cr-Zr-Y合金时效特性和力学性能的影响

探讨了不同变形量对电气化铁路接触线用Cu-0．42Cr-0．13Zr-0．11Y合金时效性能和力学性能的影响。研究结果表明，合金经950℃、1h固溶处理后施以不同程度冷变形，再进行480℃时效处理，比合金固溶后直接时效可显著提高合金的电导率和显微硬度；随变形量逐渐增大，合金强度不断升高，抗拉强度最高可达645MPa，而延伸率和导电率略有降低。当二次拉拔变形量为75．0％时，合金的抗拉强度、导电率和延伸率分别为605．6MPa、80．79％IACS和10．2％。     

TiAl合金激光表面合金化涂层的组织与耐磨性

以ＮｉＣｒ－ＷＣ混合料末为原料,对ＴｉＡｌ合金进行激光表面合金化处理,制得了以γ－ＮｉＣｒＡｌＴｉ镍基固溶体为基体,以ＴｉＣ,Ｗ２Ｃ及Ｍ２３Ｃ６为增强相的耐磨复合材料表面改性层。分析了改性层的组织,并测试了其在滑动摩擦试验条件下的耐磨性。实验结果表明,激光表面合金化涂层具有较高的硬度及较好的耐磨性。     

Microstructure and dry sliding wear resistance of CoTi intermetallic alloy

A wear resistant CoTi intermetallic alloy was fabricated by the laser melting deposition process. Microstructure of the alloy was characterized by OM, SEM, XRD and EDS and wear property was evaluated under room-temperature dry sliding wear test condition. Wear resistance of the CoTi intermetallic alloy under dry sliding wear test condition is up to 2 and 3.3 times higher than the hardened high-speed steel W18Cr4V and the bearing steel 1.0%C–1.5%Cr, respectively. The excellent wear resistance of the CoTi alloy is attributed to the inherent good toughness and strong yield-anomaly of the intermetallic CoTi as well as to the unique strong friction-induced hardening in the worn surface and subsurface of CoTi alloy under dry sliding wear process.     

氮合金化药芯焊丝对堆焊层组织和耐磨性的影响

在Cr13马氏体不锈钢药芯焊丝中添加2%铌铁、2%钒铁和5%氮化铬进行埋弧堆焊,研究氮合金化对堆焊层组织和耐磨性的影响。堆焊层试样分别在450℃、480℃、500℃、520℃、540℃、560℃和600℃下进行焊后回火处理,研究回火温度对堆焊层组织和耐磨性的影响。结果表明,焊态下硬面合金组织由马氏体、残余奥氏体和分布在基体上的碳氮化物组成。加入铌、钒和氮化铬后,组织的晶粒得到细化,耐磨性也随之提高。回火热处理使基体晶内及晶界弥散析出球状第二相粒子(Nb、V、Cr)x(C、N)y,随着回火温度的升高,氮合金化硬面合金中第二相粒子的数量先略有下降,再逐渐增加,随后急剧减少,耐磨性也相应改变。540℃时试样磨损量最小,耐磨性最佳,当回火温度升至600℃时,第二相粒子数量减少,耐磨性最差。     

Dry sliding wear of Ni alloyed austempered ductile iron

Measurements of dry sliding wear are presented for ductile irons with composition Fe-3.56C-2.67Si-0.25Mo-0.5Cu and Ni contents of 0.8 and 1.5 in wt.% with applied loads of 50, 100 and 150 N for austempering temperatures of 270, 320, and 370 °C after austenitizing at 870 °C for 120 min. The mechanical property measurements show that the grades of the ASTM 897M: 1990 Standard can be satisfied for the selected austempering conditions. The results show that wear resistance is independent of austempering temperature with an applied load of 50 N, but there is a strong dependence at higher austempering temperatures with applied loads of 100 and 150 N. Observations indicate that wear is due to subsurface fatigue with cracks nucleated at deformed graphite nodules.     

工艺参数对TiAl合金激光表面合金化改性层组织与耐磨性的 …

利用元素氮和元素碳对γ－ＴｉＡｌ合金（简称ＴｉＡｌ合金）进行激光表面合金化处理,分别制得了以ＴｉＮ及ＴｉＣ硬质耐磨相为增强相的快速凝固原位耐磨复合材料表面改性层,改性层与基体间为完全的冶金结合,其显微组织从熔池底部到自由表面具有梯度渐变特征,越接近自由表面,增强相越密集,较系统地研究了激光表面合金化工艺参数对改性层显微组织以及在磨料磨损及滑动磨损条件,增强相越密集。较系统地了激光表面合金化工艺参数     

Improvement of the wear resistance of Ti-based coating sliding against copper alloy

The multilayer coating, Ti10%-C:H/TiC/TiCN/TiN, was deposited on cemented tungsten carbide (WC-Co) substrate by an unbalanced magnetron sputtering system. Tribological characteristics of this coating were compared with the coatings of TiN, TiCN, and TiC/TiCN/TiN deposited on WC-Co substrates and the WC -Co substrate itself. The coating displayed excellent tribological properties, i.e., both low value and smooth curve of friction coefficient, and also, compared with the other tested materials, yielded the lowest wear depth when sliding against bronze under dry conditions. The coating thus protects against the high wear experienced when Ti-based coatings rub against copper alloy.