钛合金非氧化热喷涂金属钼涂层界面冶金特征

对TA7钛合金以氩气保护等离子热喷涂金属钼，并进行保温扩散处理得到的涂层界面微观结构用金相显微镜、扫描电镜、电子探针、X射线衍射等分析手段做了较详细的分析。结果表明，采用亚音速等离子热喷涂金属钼可得到致密、基本无层状结构的涂层；界面附近合金元素的相互扩散可促进形成冶金结合，并对钛合金近界面组织结构产生一定的影响。     

NiAl/NiCoCrAlY/8YSZ复合喷涂层的微观结构与性能研究

目的提高金属/陶瓷隔热涂层体系在海洋环境下的耐腐蚀性能。方法利用冷喷涂方法制备NiAl复合打底层和Ni CoCrAlY粘结层,与等离子喷涂制备的8YSZ陶瓷层构成适用于海洋环境的多层结构耐蚀隔热涂层体系。利用FE-SEM分别观察喷涂态粘结层和陶瓷层的表面、横截面形貌,通过EDS分析涂层元素分布;利用XRD分析表征涂层的物相组成;借助万能材料试验机,采用拉伸法测试涂层结合强度;利用热循环试验和焰流冲刷试验测试涂层的耐高温性能。结果微观分析表明,冷喷涂制备的NiAl复合打底层和Ni CoCrAlY粘结层形貌致密,涂层材料未发生明显氧化,颗粒变形程度不一,粘结层与基体间的结合强度约为18.4 MPa,粘结层与8YSZ陶瓷层界面结合紧密。陶瓷层物相结构和成分稳定,涂层经12次热震循环和1000个周期的高温焰流冲击后,表面未出现开裂、起皮和脱落。结论采用冷喷涂法和等离子喷涂法联合制备的耐蚀隔热复合涂层体系具备良好的耐热性和耐腐蚀性。冷喷涂制备的金属涂层结构致密,孔隙率低,与陶瓷层结合良好,能够有效提高涂层体系在腐蚀性环境中的耐蚀性能。NiAl复合涂层可以缓解Ni CoCrAlY粘结层和铝合金基材间的热匹配问题,增强涂层的结合性能。     

连接工艺参数对镍基高温合金TLP连接接头组织和性能的影响(英文)

以BNi-2为中间层对镍基合金进行过渡液相连接,研究连接工艺参数对接头组织和力学性能的影响。随着连接温度的升高或连接时间的延长,沉淀区的富镍和富铬硼化物数量减少,同时沉淀区晶粒尺寸减小。较高的连接温度或较长的连接时间,有利于降熔元素(B和Si)由沉淀区向母材中的扩散和母材与连接接头间的原子互扩散。当连接温度为1170℃、连接时间为24h时,可以获得与母材化学成分及组织基本相当的连接接头。剪切试验结果表明:室温和高温拉剪强度均随着保温时间的延长而增加,但连接时间对高温拉剪强度的影响要大于对室温拉剪强度。     

热喷涂及热处理对45钢表面组织和性能的影响

采用金相显微镜、扫描电镜分析和显微硬度测试等手段,研究了喷焊及回火温度对镍基自熔合金粉末涂层组织和性能的影响。结果表明:在结合面上,元素互相扩散,形成亮白色带状的过渡层,基体母材区受热较少,组织变化不大。碳元素扩散进入喷焊层后,与Cr形成(Fe,Ni)23C6及Cr的碳化物,这些硬质相阻碍喷焊层晶粒的张大,致使晶粒细化,在45钢中形成粗棒状或块状组织。喷焊层与基体之间形成了良好的冶金结合,合金元素在喷焊层与基体界面附近连续分布,保证了较高的结合强度。     

面向工业设计的塑料表面铝涂层的结合强度

目的采用电弧喷涂方法在环氧树脂和ABS塑料表面喷涂铝涂层,研究涂层结合强度的影响因素。方法第一组试验是塑料表面喷砂后,喷涂铝涂层;第二组是塑料表面喷砂后,涂覆一层高强度环氧树脂结构胶,再喷涂铝涂层。选择喷涂气体压力、喷涂电流和喷涂距离三因素进行正交试验,采用粘结拉伸法测试结合强度,并用照相法测量铝液和环氧树脂塑料、Q235钢的接触角。结果本试验条件下,二种塑料电弧喷涂铝涂层结合强度的影响因素主次顺序为:空气压力喷涂电流喷涂距离。最优方案是:喷涂气体压力为0.7 MPa,喷涂电流为220 A,喷涂距离为160 mm。未涂覆高强度环氧树脂结构胶的涂层,结合强度最大不超过3 MPa;涂覆高强度环氧树脂结构胶的涂层,结合强度达到近20 MPa。铝液和Q235钢的接触角是45°,和环氧树脂塑料的接触角是135°。结论环氧树脂和ABS塑料表面电弧喷涂铝涂层的结合强度低的主要原因是铝液和它们之间的润湿性差。涂覆高强度环氧树脂结构胶后,喷涂工艺参数对涂层的结合强度影响不明显,结合强度受控于环氧树脂结构胶的粘接作用,使涂层的结合强度显著提高。     

钼及钼合金表面高温防护涂层的研究进展

系统总结了国内外关于钼及钼合金表面高温防护涂层的最新研究成果，分析了钼在不同温度区间的氧化特征，并基于涂层组织结构稳定性、涂层缺陷、涂层与基体界面结合强度、界面物理和化学相容性、氧扩散等多方面，概述了钼及钼合金表面高温防护涂层的性能要求。归纳了现阶段应用于钼及钼合金表面的高温防护涂层体系，主要包括单一硅化物涂层、改性的硅化物涂层、硅化物基梯度复合涂层、铝化物涂层、耐热合金涂层和氧化物涂层，重点讨论了涂层的成分和结构对其抗高温氧化性能的影响。同时，对比介绍了钼及钼合金表面高温防护涂层常用的制备方法，主要包括料浆烧结法、包埋渗法、等离子喷涂法、熔盐法、化学气相沉积法、磁控溅射法等。最后，对钼及钼合金表面高温防护涂层现阶段存在的问题及未来发展方向进行了展望。     

Aufbau und Eigenschaften thermisch gespritzter Auskleidungen aus Sondermetallen

Structure and properties of special metal coatings applied by thermal spraying Thermal spraying of metals of groups IVa, Va and VI a is difficult because of the fast oxidation of these metals (Ti, Zr, Ta, Nb, W, Mo). It is consequently of vital importance that the atmosphere be oxygen-free, it is that the spray process is carried in an inert atmosphere. In view of the high cost involved in such a system it is necessary to provide for recirculation of an inert gas. The coatings obtained in pure argon are characterized by very high adhesion strength which is due to diffusion phenomena at the base metal/coating interphase. This diffusion takes place at high velocities and the thickness of the diffusion layer depends from the state of perturbation of the superficial zone of the base metal (e. g. perturbation due to sand blasting) and of the perturbation of the atomic structure of the liquid particles at the high temperature. Titanium coatings thus obtained are completely free from inclusions when obrained in argon, while they are severly embrittled when applied under nitrogen. The properties of coatings from all the metals considered (Ti, Zr, Mo, Nb, Ti6A14V) are perfectly comparable to those of the solid metals.     

Tribological characteristics of high strength steel sheets under hot stamping conditions

Nowadays, the hot stamping of high strength steel sheets is currently utilized to produce automotive components characterized by a high strength-to-weight ratio and an increased resistance to impact. In order to avoid scaling and decarburization during the heating stage, the metal sheets are coated with a specially developed Al-Si coating that have proved a relevant influence also on the tribological behaviour of the metal sheets during the forming stages. The paper presents a fundamental study about the sheet coating characteristics in terms of morphology, surface roughness and tribological behaviour as a function of the process parameters typical of industrial hot stamping processes. The presented results show that the blank heating promotes the iron diffusion into the Al-Si coating giving form to an Al-Fe-Si ternary alloy whose characteristics depend on the thermal cycle parameters; moreover, it is proved that the tribological characteristics of the metal blank surface in terms of friction coefficient depend on the blank temperature and contact pressure.     

DIFFUSION BONDING OF SUPERPLASTIC AI ALLOY LC4

Diffusion bonding of supcrplastic Al alloy LC4,with prior surface treatment of organicsolution protecting coating after electroplishing and stainless steel wool brushing,wasperformed by Gleeble test machine under conditions ranged 490—530 ℃,1.0—3.0 MPa.30—180 min and vacuum of 1.0×10~(-3) Pa.The joints were examined to have similarstrength and microstructure to the base metal Discussion was made on the effect ofsuperplastic treatment on bonding.The micromechanism for diffusion bonding of super-plastic metal was suggested as the migration of original bond interfaces caused by atomicdiffusion and grain growth. Experimental results for the alloy as quench-aged state werepresented to compare with the superplastic one.     

FeAl系电热爆炸等离子体喷涂层高温耐蚀性能研究

利用金属导体FeAl系合金箔,电热爆炸产生的瞬间高能量冲击波效应,制备FeAl、FeCrAl、FeCrAlRE等离子体喷涂层。通过涂层SEM等检测,可以看出涂层致密,同时涂层与基体可以形成冶金结合层,涂层与基体之间存在明显的过渡层。经高温氧化、氯化、硫化耐蚀性测试,得出3种等离子体喷涂层的腐蚀变化规律,从而优选出耐高温腐蚀的FeCrAlRE电热爆炸等离子体涂层。     

扩散退火和热轧温度对钛铜界面结合强度的影响

对热挤压的钛铜复合棒进行扩散处理,研究扩散退火温度及保温时间对界面结合强度的影响,并通过测试Ti和Cu在高温下的拉伸性能来选择较为合适的热轧温度。结果表明:扩散退火可有效促进界面处金属原子的扩散和增强结合强度,当扩散退火在780～800 ℃/30 min时复合界面的结合强度最高;钛铜复合棒热轧温度应选择780 ℃较为合适,此时Ti、Cu的强度和塑性指标相近,利于热轧时的均匀变形;钛铜复合棒的热轧结合机理可用N.Bay理论、热作用机制及位错学说进行解释。     

棒材等离子喷涂法制备Fe72Cr8P13C7非晶态合金涂层成型特征

采用棒材等离子喷涂法制备Fe72Cr8P13C7非晶态合金涂层，分析了涂层的组织，测定了晶化温度、显微硬度和结合强度，采用扫描电镜观察涂层的微观形貌和截面形貌，能谱分析涂层正面和截面的成分变化。结果表明，涂层组织致密，均匀，Cr、P在涂层中片状结构表面有富集现象，涂层与基材之间有冶金结合、机械结合的成型特征。     

Be/CuCrZr合金扩散连接的界面行为

在不同表面粗糙度的Be侧镀Ti/Cu中间层,采用热等静压技术将铍与CuCrZr合金进行扩散连接。通过AES、SEM(EDS)、室温剪切试验和XRD等分析其镀层形貌及成分、界面特性与相结构。结果表明:9μmTi、35μmCu镀层带征较为均匀,影响扩散连接强度的元素较少,采用双靶单侧镀复合膜的工艺有利于减少Ti镀层的氧化;界面剪切强度明显提高,最高可达243MPa,Be表面粗糙度的不同对强度影响不明显;Be-Ti连接强度高,剪切断裂均发生在Cu镀层。     

Characterization of Transient Liquid-Phase Bonded Joints in a Copper-Beryllium Alloy with Silver-base Interlayer

Transient liquid-phase diffusion bonding was employed to join copper-beryllium alloy using three silver-base interlayers. The bonding process was carried out at different temperatures under argon and vacuum atmospheres for various hold times. Interfacial microstructures were examined by scanning electron microscopy. Microhardness, tensile, and fatigue tests were used for evaluating the mechanical properties. Maximum tensile strength of 156.45?MPa was obtained for bonds processed at 780?°C. Fatigue strength of bonds fabricated in vacuum was higher than those of bonds prepared in argon atmosphere. The diffusion of the main elements from the interlayers into the base metal was the main controlling factor pertaining to the microstructural evolution of the joint interface.     

超音速等离子喷涂工艺参数对AlSi20%Al/Ni涂层结合强度的影响

为使AlSi-20%Al/Ni超音速等离子喷涂涂层获得优良的结合性能,采用正交实验法研究了喷涂距离、喷涂电压、喷涂电流等喷涂工艺参数对结合强度的影响。利用X射线衍射、扫描电镜等手段对涂层的相组成和断口形貌进行分析,利用WDW-E100D微机控制式万能拉伸试验机对涂层结合强度进行测试。结果表明:涂层由AlSi和AlNi两相组成,影响AlSi-20%Al/Ni涂层结合强度工艺参数的主次顺序为喷涂距离、喷涂电压、喷涂电流,优化后的工艺参数为主气流量3.2m3/h,喷涂电流为380A,喷涂电压为130V,喷涂距离为90mm,在此参数下制备的涂层组织致密,其结合强度为65.5MPa。     

FeAl系电热爆炸喷涂层抗高温腐蚀性能

FeAl系合金箔在电热爆炸过程中产生瞬间冲击波效应,在45G钢上制备了FeAl、FeCrAl、FeCrAlRE三种等离子体喷涂层。通过SEM等测试手段对比分析涂层腐蚀前后组织形貌,可以看出涂层具有纳米晶、微米晶组织结构,同时涂层与基体形成冶金结合层,涂层与基体之间存在较为明显的过渡层。经高温氧化耐蚀性测试,得出三种等离子体喷涂层的腐蚀变化规律,从而优选出耐高温腐蚀的FeCrAlRE电爆喷涂等离子体涂层。     

Interfacial bonding state on different metals Ag, Ni in cold pressure welding

1　INTRODUCTIONThetechnologyofcoldpressureweldingiswide lyusedtoachievethejoiningofthesameordifferentmetalswithdifferentthermophysicalpropertiesandotherconditions ,foritsparesenergysources,simpli fiesweldingequipments,doesnotneedtobeheated ,anddoesnotcausethemelting ,theheateffectzoneandthebrittlecompounds .Accordinglythetechnolo gymaybesatisfiedwiththedemandofcomprehen sivepropertiesinindustryapplication ,andwillsolvetheconflictbetweentheincreasingdeficienciesandgrowingdemands .Onthesideo…     

耐热钢管的瞬时液相扩散焊工艺研究

用BNi2,Fe78Si9B13和FeNiCrSiB合金箔作中间层,氢气保护,分别对TP304和T91钢管进行了瞬时液相扩散(TLP)连接。分析了TLP连接接头的显微组织、力学性能和元素分布;确定出了合适的连接工艺参数。研究表明,TP304用BNi2和FeNiCrSiB作中间层,T91用FeNiCrSiB作中间层连接的接头室温下的抗拉强度和抗弯强度等于或超过基体。     

湿法超声机械镀锌技术研究

目的改进滚筒式机械镀锌设备对零件尺寸的限制,实现较大尺寸零件的机械镀锌。方法提出一种新的机械镀锌工艺,即用超声振动系统为冲击介质提供动力,冲击锌粉颗粒到工件表面,形成镀锌层。观察镀锌层的微观表面形貌和断面形貌,测试镀锌层的结合强度,利用中性盐雾试验评判镀锌层的耐腐蚀性能。结果在工件表面获得了一定厚度的镀锌层,镀层表面细腻、均匀、平整,无凹凸不平结构。镀层是由锌粉颗粒镶嵌、填充而成的致密堆积体,与基体的结合强度高,耐腐蚀性能好。结论湿法超声机械镀锌工艺可以对较大尺寸零件进行机械镀锌。     

可控气氛下梯度涂层组织与结合性能分析

陶瓷梯度涂层的性能优良,在大气氛围下等离子喷涂制备的涂层会受到空气的氧化.针对这一情况,在可控气氛(氩)中采用等离子喷涂方法制取了Ni-Cr-B-Si/Al<,2>O<,3>的梯度涂层,与在空气中制取的Ni-Cr-B-Si/Al<,2>O<,3>梯度涂层进行了对比.分析了氩气氛围对梯度涂层显微组织和结合强度的影响.结果...