车用不锈钢表面激光原位合成FeCrCoNi涂层组织及耐磨性

为提升车用316不锈钢的表面硬度及耐磨性,采用激光熔覆原位合成法在316不锈钢表面制备FeCrCoNi高熵合金涂层。分别对FeCrCoNi高熵合金涂层的相组成、元素分布、显微硬度及耐磨性进行研究。结果表明：原位合成制备的FeCrCoNi高熵合金涂层无裂纹、气孔等缺陷,与基材呈现良好的冶金结合。FeCrCoNi高熵合金涂层由单一的FCC相组成,涂层组织为树枝晶。各元素分布均匀,无明显偏析。FeCrCoNi高熵合金涂层的截面平均显微硬度约为283.7 HV,相较于316不锈钢基体提升了约50%。FeCrCoNi高熵合金涂层的平均摩擦因数分别为0.377和0.438,比磨损率分别为2.27×10^-5mm³/N·m和6.17×10^-5mm³/N·m,FeCrCoNi高熵合金涂层的磨损率降低了70%。FeCrCoNi高熵合金涂层的磨损机制为磨粒磨损。     

CeO2添加量对45钢表面激光熔覆Ni-WC涂层的组织和性能影响

利用二氧化碳激光器在45钢基体表面上熔覆Ni-WC-CeO₂的复合涂层,使用扫描电镜、EDS、显微硬度计、洛氏硬度计,研究CeO₂添加量对Ni-WC-CeO₂复合涂层宏观形貌、显微组织、元素分布、表面硬度及纵截面显微硬度的影响,以找到最佳的CeO₂添加量。CeO₂的添加有助于改善涂层宏观形貌、基体和涂层的扩散及浸润性,细化微观组织及WC形貌,提高涂层表面硬度和纵截面显微硬度。CeO₂添加量存在一个最佳值：当CeO₂添加量为0.3%时,Ni-WC-CeO₂复合涂层表面无渣、无裂纹、较小润湿角,宏观形貌最好,从表面到与基体结合处涂层显微组织无枝晶,组织明显细化,Ni-Cr合金与WC间、涂层与基体间的元素发生明显互扩散,碳化钨形貌细化且分布较为均匀,涂层表面硬度最高,所有涂层纵截面显微硬度均呈现中间高两端低的“山形”分布;当CeO₂添加量为0.25%时,每组纵截面显微硬度几乎都高于其他CeO     

等离子熔覆(Cr,Fe)7C3/γ-Fe复合涂层的组织与耐磨性

以Fe-Cr-C合金粉末为原料,利用等离子熔覆技术在45号钢表面制备了(Cr,Fe)7C3/γ-Fe复合涂层.并对涂层的显微组织、显微硬度和室温干滑动实验进行了具体分析.结果表明涂层组织包括初生相(Cr,Fe)7C3以及γ-Fe与(Cr,Fe)7C3组成的共晶;其组织有明显的由基材到涂层外延生长的特征,结构均匀,与基材之间为完全冶金结合;且具有较高的硬度及合理的硬度梯度.该涂层在室温干滑动磨损实验条件下具有优异的耐磨性.     

热处理对AlCrFeNiTi高熵合金组织和硬度的影响

在氩气保护下用真空电弧炉制备了AlCrFeNiTi高熵合金,采用X射线衍射仪、金相显微镜和维氏硬度计等研究了加热温度、保温时间和冷却方式对AlCrFeNiTi高熵合金组织和硬度的影响。结果表明,铸态AlCrFeNiTi高熵合金由两个体心立方结构固溶体构成,形成了由枝晶、枝晶间和α+β共晶组织组成的典型高熵合金枝晶组织。随着加热温度的升高,合金枝晶相先粗化,当温度升至900℃时再细化;随着保温时间增加和冷却速度减慢,枝晶组织和共晶组织均粗化,而合金硬度呈上升趋势。合金经过热处理后的硬度取决于枝晶相含量和形貌,在高速冷却方式下残余内应力对合金的硬度也起关键作用。     

Y2O3对AlCoCrFeNi高熵合金涂层组织及力学性能的影响

利用激光熔覆技术在Q235钢基体表面分别制备出添加不同质量分数Y₂O₃的AlCoCrFeNi高熵合金涂层。采用X射线衍射仪、扫描电子显微镜、显微硬度计和摩擦磨损试验机对AlCoCrFeNi高熵合金涂层的微观组织、硬度及摩擦磨损性能进行了分析。结果表明:AlCoCrFeNi高熵合金涂层由面心立方结构（FCC）和体心立方结构（BCC）两相构成;随着Y₂O₃质量分数的提高,其体心立方结构相体积分数增加,而面心立方结构相的体积分数变化呈相反趋势。AlCoCrFeNi高熵合金涂层组织由等轴晶构成,加入Y₂O₃后,促进了熔池流动,使气孔逐渐消失,致密性提高,晶粒明显细化。添加质量分数5%Y₂O₃的涂层组织呈树枝晶状,形成弥散分布的YAl₂和Y₂O₃相;涂层的显微硬度可达HV 350,约为AlCoCrFeNi高熵合金涂层硬度的2倍,强化效果明显。Y₂O₃的添加有利于促进涂层中体心立方相的形成和YAl₂相的析出,能有效提高高熵合金涂层的硬度及耐磨性能。     

T10钢表面FeMoCoNiCrTix高熵合金熔覆层组织及性能

采用激光熔覆技术在T10A钢表面制备了FeMoCoNiCrTi_x（x分别为0.25,0.50,0.75,1.00）高熵合金熔覆层,分析了试样熔覆层及基体界面处的相结构及组织,并利用显微硬度计测试了试样处理前后的截面硬度变化。研究表明,经过激光熔覆在T10A钢表面得到的高熵合金层主要由NiCrFe、NiCrCoMo 2种固溶体为主,其结构分别为BCC结构和FCC结构,熔覆层的组织以柱状枝晶为主,界面处出现等轴晶;随着Ti含量增多,熔覆层由固溶强化变为固溶体与硬质相混合强化,熔覆层的HV硬度达到了792,热影响区的HV硬度达到了620,均高于基体硬度。同时耐磨损性能有了明显提高,磨损方式由粘着磨损逐渐变为磨粒磨损。      

激光熔覆涂层的界面组织和冲击载荷作用下的性能

45钢及1Cr18Ni9Ti表面采用激光熔覆WFCL-11涂层,研究了该涂层与基体界面及表面显微组织和硬度,分析了在冲击载荷作用下,显微组织、结合性能、硬度变化等特点.研究了不同基材与熔覆材料对结合面性能的影响.     

高温合金表面激光熔铸镍基合金涂层的组织与耐磨性能

研究了高温合金ＧＨ３３表面激光熔铸镍基合金涂层的组织和耐磨性能。结果表明,基材对涂层合金的稀释作用较小;涂层与基材之间形成良好的冶金接合;涂层基体组织为γ－Ｎｉ枝晶,枝晶间为γ－Ｎｉ、Ｍ２３（ＣＢ）６、Ｎｉ３Ｂ、Ｃｒ２Ｂ、ＣｒＢ、ＷＣ等;涂层耐磨性能的平均值较基材提高４倍以上。     

激光熔覆(FeCrCo/Ni)_5-SiTiNbMoW高熵合金涂层组织及性能研究

通过激光熔覆技术在工具钢表面成功制备(FeCrCo/Ni)_5-SiTiNbMoW高熵合金涂层,并采用带有能谱仪的扫描电镜(SEM/EDS)、X射线衍射仪(XRD)、显微硬度计对涂层组织、成分、物相和硬度进行分析测试。结果表明,(FeCrCo)_5-SiTiNbMoW涂层含有BCC主相、少量MC相及Laves相,(FeCrNi)_5-SiTiNbMoW涂层含有FCC主相及少量MC相、Laves相;两种涂层组织均以树枝晶为主,(FeCrNi)_5-SiTiNbMoW涂层组织中同时还出现共晶组织。(FeCrCo)_5-SiTiNbMoW高熵合金涂层的显微硬度略高于(FeCrNi)_5-SiTiNbMoW高熵合金涂层。     

烧结熔覆钢表面镍基合金涂层的组织和性能

采用Ni25、Ni45、Ni60合金粉末通过烧结熔覆法在45钢表面制备出不同成分的镍基合金涂层。通过金相显微镜观察和X射线衍射分析等手段对合金涂层的组织形貌、相组成和界面结构进行研究,并对涂层显微硬度进行了测试。结果表明：通过烧结熔覆可以在45钢表面获得较为致密的镍基合金涂层。Ni25合金涂层组织主要为比较粗大的γ-(Ni, Fe)奥氏体以及少量的Cr₂₃C₆碳化物相;Ni45和Ni60合金涂层中除了γ-(Ni, Fe)奥氏体和Cr₂₃C₆碳化物之外,还出现了CrB硼化物。不同成分镍基合金涂层与45钢基体在界面处均形成了良好的冶金结合。当烧结温度1100℃、保温时间15 min时,涂层微观组织致密,硬质相颗粒尺寸较小,分布均匀。Ni60合金涂层的硬度最高,约为HV 735;Ni45合金涂层次之,约为HV 534;Ni25合金涂层硬度最低,只有HV 236。     

激光熔覆高熵合金涂层组织结构及强化机理研究进展

激光熔覆作为一种绿色、高效的表面处理技术,能够快速制备组织致密、晶粒细小,与基体呈高强度冶金 结合的涂层,是近年来高熵合金领域的研究热点之一。概述了现有高熵合金涂层材料体系和制备方法,重点讨论 了激光熔覆CoCrFeNi-M 典型过渡族高熵合金涂层的组织结构,及其耐磨、耐蚀、抗高温氧化等性能,并归纳了 涂层的强化机制和方法。CoCrFeNi-M 系合金涂层主要呈现FCC 固溶体结构,综合力学性能普遍较好,通过合金 体系调控,在细晶强化、固溶强化、第二相强化等作用下,能够获得硬度、耐磨性、耐蚀性等性能的进一步提升。 同时,概述了激光熔覆难熔高熵合金涂层的组织结构,耐磨、耐蚀、抗高温氧化性能及性能强化机制,该体系合 金涂层主要呈现BCC 固溶体结构,硬度较高但室温韧性普遍不足,具有较好的高温强度,在高温领域具有较好 的应用前景,但抗高温氧化性能普遍不足,仍需通过合金体系优化进一步提升。此外,总结了基于激光熔覆技术 开展的高熵合金涂层制备及研究中存在的问题和不足,并展望了未来的发展方向。     

Plasma coatings of (TiCrC)-(FeCr) composite powder alloys: Structure and properties

The coatings of the (TiCrC)-(FeCr) composite are deposited on steel and titanium alloy by plasma method. The composition, structure, and tribotechnical properties of these coatings are studied in comparison with traditional materials based on the Ni-Cr alloy. The effect of preliminary surface treatment methods, i.e., sandblasting treatment and electrospark alloying, on coating properties is examined. The fretting corrosion of coatings is investigated. It is established that coatings based on double titanium-chromium carbide have considerably greater wear resistance than that of Ni-Cr alloys at almost equal friction coefficients. It is established that electrospark alloying is competitive with traditional sandblasting treatment in environmental effect and coating-to-based adhesion. __________ Translated from Poroshkovaya Metallurgiya, Vol. 46, No. 3–4 (454), pp. 37–45, 2007.     

Surface aluminum alloy formation by electrodeposition from alkali chloride melts and by laser techniques

The work presented here deals with the surface aluminum alloys formation on AFNOR 35NCD16 steel substrate using two different methods: electrolytic surface alloy formation followed by a laser surface melting; laser surface alloying by aluminum powder injection in the remelted surface. The electrolytic-formed alloy presents the highest microhardness values (900 HV_80g) in comparison with that measured on the aluminum surface alloy obtained by laser techniques (520 HV_80g) and 550 HV_80g). Al₅Fe₂ phase was the only one identified in the electrolytic coating, before laser treatment. After laser melting of the electrolytic deposit, AlFe₃ phase is present. In the case of laser alloy formation by aluminum powder injection non-alloyed aluminum as well as the AlFe phase was identified.     

Microstructure and properties of CrMnFeCoNi high-entropy alloy prepared by mechanical alloying and spark plasma sintering

The equiatomic ratio CrMnFeCoNi high entropy alloy (HEA) was prepared by mechanical alloying (MA) and spark plasma sintering. This paper reports the behaviour of MA, the phase formation, microstructure and mechanical properties of CrMnFeCoNi HEA. With the increase of milling time, solid solution with single FCC phase was gradually formed. The single FCC phase remained as matrix after SPS at 1373?K and 50?MPa. Ultrafine-grained microstructure and good mechanical properties were obtained: At room temperature, the as-sintered bulks exhibit an excellent combination of high compressive strength (2390?MPa) and high fracture strain (47%).     

Influence of Chemical Composition of Mg Alloys on Surface Alloying by Diffusion Coating

A recently developed technique of surface alloying by diffusion-coating has been used to produce coatings on Mg alloys with various Al and Zn contents. The experimental results show that both Al and Zn solutes in the alloy promote the diffusion of alloying elements through grain refinement of the substrate alloys and through reduction of diffusion active energy because of the reduction of melting temperature of the alloys. Therefore, the efficiency of surface alloying increases by diffusion coating. Thick, dense, uniform, and continuous layers of intermetallic compounds, which consist of a τ-phase layer and a β-phase layer, can be produced on the surface of various Mg alloys. The intermetallic compound layers not only have microhardness values that are 4 to 6 times higher than the substrate but also provide effective protection of the Mg alloys from corrosion in 5 pct NaCl solution at room temperature.     

Features of formation and the structure,composition, and properties of electrospark coatings on the ZhS6U nickel alloy with the use of the KhTN-61 SHS-Ts alloy

Features of the mass transfer of a KhTN-61 SHS-Ts electrode material onto a substrate of a ZhS6U nickel alloy with a variation in frequency (1000–1400 Hz) and time (25–70 μs) of pulsed discharges was studied. A complex of studies of the structure, composition, and properties of the formed coatings was carried out. The optimum frequency-energetic mode of the treatment (E = 0.30 J, f = 1000 Hz, and τ = 50 μs), which was characterized by a high rate of coating at a satisfactory degree of the roughness of the surface layer, is found. As a result of electrospark alloying (ESA) at the optimum energetic parameters, 40-μm-thick coatings with a uniformity of 95% and a microhardness of 5.2 GPa form on the surface of the nickel alloy. The ESA treatment of a ZhS6U nickel alloy with the use of KhTN-61 SHS-Ts electrode material allows us to enhance its wear resistance (by more than a factor of 10), hardness (by a factor of 2), and heat resistance, as well as to decrease (by a factor of 5) the friction coefficient.     

陶瓷颗粒强韧化Fe基非晶合金复合涂层硬度的研究

通过大气等离子喷涂技术（APS）在Q235基体上制备了一种Al2O3-13%TiO2颗粒增强的Fe基非晶态合金涂层。利用光学显微镜（OM）、X射线衍射仪（XRD）、扫描电子显微镜（SEM）、显微硬度计（MHT）和纳米压痕仪对该涂层的显微组织结构、相组成以及弹性模量等进行了研究。结果表明：采用APS喷涂技术制备的该涂层由...     

等离子表面冶金铁基合金层磨粒磨损机理

 采用等离子表面冶金技术,在Q235钢表面获得铁基冶金层,并对其进行磨粒磨损实验。实验结果表明,冶金层耐磨性比淬火45号钢有较大提高。等离子表面冶金层磨粒磨损机制主要为两种类型：①塑性变形－切削;②断裂－剥落。磨损过程为两种机制综合作用的结果,冶金层组织对磨粒磨损机制有显著影响。     

等离子喷涂FeCrMoSnPBSiC非晶合金涂层的结构和性能

 将软磁非晶合金FeCrMoSnPBSiC粉末作为喷涂材料,用大气等离子喷涂法在Q235钢板表面制备非晶态合金涂层。结果表明,该非晶态合金涂层组织致密均匀,具有较高的硬度,平均显微硬度为HV01 644,涂层与基材结合强度超过25 MPa,而且涂层具有较高的热稳定性和较好的耐腐蚀性能,起始晶化温度约516 ℃,在5%NaCl溶液中具有钝化作用。