H13钢表面激光熔覆NbC/Ni60复合涂层组织及高温耐磨损性能

目的 研究NbC颗粒的加入量对H13钢表面激光熔覆NbC/Ni60复合涂层的组织、硬度和耐磨性的影响。方法 将Ni60合金粉末与NbC碳化物粉末球磨混合,采用激光熔覆技术,在H13钢基体表面制备不同NbC含量(质量分数分别为0%、10%、20%、30%)增强的NbC/Ni60合金复合涂层。采用电子扫描显微镜(SEM)、X射线衍射仪对复合涂层的微观组织和物相进行分析。借助显微硬度计,研究复合涂层的截面显微硬度分布规律。采用高温摩擦磨损试验机测试复合涂层在真空400℃下的摩擦磨损性能。结果 在激光熔覆NbC/Ni60复合涂层中,物相主要由γ-(Ni, Fe)固溶体、Ni₂Si、CrB、Cr₂₃C₆、NbC组成;熔覆层以胞晶和枝晶为主,NbC含量对复合熔覆层组织及形态具有显著影响,加入少量NbC可使熔覆层组织细化;在NbC的质量分数为20%时,大量弥散的Nb C颗粒在枝晶间呈聚集趋势;在NbC的质量分数为30%时,熔覆层中NbC相呈现块状、花瓣状形貌。NbC/Ni60复合涂层的硬度显著高于H13钢基体,随着NbC含量的增加,N...     

H13钢激光熔覆TiC/Ni合金复合涂层的组织与耐磨性北大核心CSCD

为提高H13模具钢的耐磨性能,利用激光熔覆技术,在H13钢表面制备了不同Ti C含量的Ti C/Ni基合金复合涂层,通过显微组织观察、硬度测试、滑动摩擦磨损试验方法对H13钢表面激光熔覆的不同复合涂层的组织及耐磨性能进行分析测试。结果表明,Ni60+Ti C激光熔覆涂层中物相主要为γ-(Fe,Ni)、Fe3C、Cr23C6、Ni2Si及Ti C,激光熔覆层具有较高显微硬度,Ti C的加入及含量增加可使熔覆层组织细化,复合熔覆层硬度提高,Ti C含量为30%时熔覆层内平均硬度最大,为873 HV0.2;激光熔覆Ti C+Ni60复合涂层的耐磨性显著高于H13钢基体,随Ti C含量增加而先增加后降低,Ti C含量20%耐磨性较佳;H13钢基体的磨损机制主要以犁削、切削为主,激光熔覆Ti C/Ni合金复合涂层以脆性剥落机制为主。     

H13钢激光熔覆TiC/Ni合金复合涂层的组织与耐磨性

为提高H13模具钢的耐磨性能,利用激光熔覆技术,在H13钢表面制备了不同Ti C含量的Ti C/Ni基合金复合涂层,通过显微组织观察、硬度测试、滑动摩擦磨损试验方法对H13钢表面激光熔覆的不同复合涂层的组织及耐磨性能进行分析测试。结果表明,Ni60+Ti C激光熔覆涂层中物相主要为γ-(Fe,Ni)、Fe3C、Cr23C6、Ni2Si及Ti C,激光熔覆层具有较高显微硬度,Ti C的加入及含量增加可使熔覆层组织细化,复合熔覆层硬度提高,Ti C含量为30%时熔覆层内平均硬度最大,为873 HV0.2;激光熔覆Ti C+Ni60复合涂层的耐磨性显著高于H13钢基体,随Ti C含量增加而先增加后降低,Ti C含量20%耐磨性较佳;H13钢基体的磨损机制主要以犁削、切削为主,激光熔覆Ti C/Ni合金复合涂层以脆性剥落机制为主。     

SiC/Ni基合金激光熔覆层磨损性的研究

采用扫描电子显微镜、盘销式摩擦磨损试验机等方法对45钢表面SiC／Ni基合金激光熔覆层的组织和磨损性进行了试验分析。结果表明,激光熔覆后试样从表面至心部可分为熔覆区、结合区、热影响区和基体。熔覆层显微组织以枝状晶和胞状晶为主,结合层以细晶为主,激光熔覆层与基体结合良好。磨损试验结果显示激光熔覆可显著改善钢的耐磨性,SiC／Ni基合金复合熔覆层比Ni基合金熔覆层具有更好的耐磨性;在一定成分范围内,适当提高熔覆层中SiC的含量,可提高材料的耐磨损性能。     

氩弧熔覆Ti-C-WC增强镍基复合涂层组织和性能分析

以Ti粉、C粉、WC和Ni60A粉末为原料,利用氩弧熔覆技术在Q235钢基材表面成功制备出Ni基增强相复合涂层,应用OM,SEM,XRD对复合涂层的显微组织和物相进行了分析.结果表明,复合涂层物相由TiC和(Ti,W)C颗粒,γ-Ni奥氏体枝晶和枝晶间的M23C6共晶组织组成,TiC颗粒相细小弥散的分布在基体上,颗粒尺寸大约1.5μm.显微硬度和耐磨性测试结果表明,涂层的显微硬度较基体Q235钢提高4倍以上;常温干滑动磨损条件下,复合涂层具有优异的耐磨性.     

TC4钛合金表面等离子熔覆Ni60涂层的性能

以等离子熔覆方式在TC4钛合金表面制备Ni60熔覆层,通过X射线衍射、扫描电镜和显微硬度测试等方法分析Ni60熔覆层凝固组织、成分及硬度的关系。结果表明:在Ni60粉末熔覆层中,由基底依次凝固生长柱晶、枝晶、等轴晶和共晶组织,在柱晶及枝晶主干等部位,Ti优先选择固溶N/O元素,将其他合金元素排挤到后凝固的等轴晶区,在最后凝固区形成富含Ni的共晶组织。熔覆层中先凝固的柱晶及枝晶区,一次时效(600℃/1 h)后获得的强化效果最佳;而后凝固的等轴晶区与共晶区,富含多种合金元素,经三次时效后,表面等轴晶区硬度强化效果依次递增,最终硬度可达800 HV。与TC4钛合金相比,Ni60熔覆层具有更优异的耐磨性和耐蚀性,三次时效后的Ni60涂层磨损失重从0.057 4 g降至0.017 1 g,耐磨性提高约3倍。     

氩弧熔覆SiC/Ni复合材料涂层组织与抗磨性分析

以Ni60A粉、SiC粉为原料,利用氩弧熔覆技术在Q235钢基材表面制备出复合涂层,应用SEM和XRD方法分析了涂层的显微组织.结果表明,复合涂层与基材实现了良好的冶金结合,复合材料涂层无单独的SiC,而是由Ni3 Si枝晶、M7 C3和γ-Ni固溶体组成,.Ni3Si枝晶均匀的分布γ-Ni固溶体基体上,涂层的显微硬度达到1 100HV0.2,涂层的耐磨性较基体提高近13倍.     

冷喷涂辅助原位合成CuNiCoFeCrAl2.3 高熵合金涂层组织与性能研究

目的 为了提升普通金属材料的表面耐腐蚀和耐磨性能,提出了一种在普通金属材料表面制备性能良好的CuNiCoFeCrAl2.3高熵合金涂层的技术工艺。方法 利用冷喷涂技术在45#钢基体上制备混合金属涂层,再经过感应重熔技术将混合金属涂层原位合成为CuNiCoFeCrAl2.3高熵合金涂层。通过采用扫描电子显微镜（SEM）、X射线衍射仪（XRD）、能谱仪（EDS）、显微硬度计、磨料磨损试验机等,对涂层的相组成、显微组织、硬度、耐磨性进行分析。结果 原位合成CuNiCoFeCrAl2.3高熵合金涂层组织致密,元素均匀分布,合金涂层由简单的BCC相构成,涂层的微观组织呈现出典型的枝晶结构。内枝晶区主要富含Co、Cr、Fe和Ni,枝晶间区则富含Cu和Al。CuNiCoFeCrAl2.3高熵合金涂层的显微硬度是45#钢基体的3倍,在干摩擦条件下,CuNiCoFeCrAl2.3高熵合金涂层在摩擦过程中以磨粒磨损为主,涂层在干滑动条件下的磨损率比45#钢基体的磨损率低59%,摩擦因数为0.38,约为45#钢基体的56%,CuNiCoFeCrAl2.3高熵合金涂层的磨损率为2.95×10?5 mm3/(N·m)。结论 使用冷喷涂辅助原位合成CuNiCoFeCrAl2.3高熵合金涂层具有很高的硬度和良好的耐磨性能。     

模具钢的局部合金化

对热作和冷作模具钢(AISIH13和D3)的表面进行了局部合金化处理的试验。在试样表面用等离子喷镀钼钢、钒钢及硼钢粉末。由电子束按照不同的参数熔化喷镀层及基体。测定了局部熔化层中的合金元素的分布、显微组织、相及硬度。也测量了局部合金化层的回火抗力。采用不同的熔化参数, 熔化层中合金元素的含量也不同。合金化层的特点在于硬度和回火抗力。建立了电子束局部合金化层的合金元素含量、显微组织、相及机械性能之间的关系。     

Cr12MoV钢表面激光熔覆多层Ni基合金涂层的组织及性能

使用脉冲Nd:YAG激光器在Cr12MoV模具钢表面熔覆了Ni20Cr和Ni60A多层Ni基合金耐磨涂层,并使用X射线衍射仪、扫描电镜及能谱仪分析了涂层的物相和显微组织。同时运用显微维氏硬度计以及高速往复摩擦磨损试验机对比分析了涂层与基体的硬度及耐磨性。结果表明,采用Ni20Cr作为打底层的多层Ni基合金涂层,能有效改善涂层与基体的冶金结合,大大减少涂层中的裂纹、气孔等缺陷。涂层表面物相主要为g-(Fe, Ni)、FeNi₃、BNi₃、Cr₃C₂以及Ni-Cr-Fe;涂层底部至表面的组织为胞状树枝晶、柱状树枝晶、择优生长树枝晶以及等轴树枝晶。Ni60A涂层大大提高了Cr12MoV模具钢的表面硬度,涂层表面显微硬度最高可达到1000 HV0.2,是基体的1.6倍。Ni60A涂层耐磨损性能明显优于基体,较基体提高了2.0~3.3倍。在Cr12MoV模具钢表面激光熔覆多层Ni基合金涂层后,形成了Cr₃C₂、Ni-Cr-Fe等硬质相,可有效提高其表面的硬度和耐磨性,起到降低模具在使用过程中因摩擦磨损而报废的概率,从而进一步延长模具的使用寿命。     

Laser cladding of high-entropy alloy on H13 steel

High-entropy alloy layer up to 150 lm in thickness was formed on H13 substrate with a metallurgical bonding at the coating/substrate interface. Simple solid solution phases were formed in the coating layer with a typical microstructure composed of both dendrite and interdendrite. The microstructure at the top of the cladding zone consists of equiaxed grains while that at the bottom consists of columnar grains. The coating layer exhibits great enhancement in microhardness and wear resistance compared with the H13 substrate.     

Laser Surface Cladding of Plastic-Molded Steel 718H by CoCrMo Alloy

With the purpose of enhancing the surface properties of plastic-molded steel 718H, in this study, a wear-resistant CoMoCr alloy cladding layer was obtained using laser surface cladding technology. Laser surface cladding was carried out by melting the CoMoCr alloy powder (particle size 15-45???m) supplied through a pneumatically driven powder delivery system with a 5-kW continuous wave (CW) CO₂ laser with the wavelength 10.6???m. The microstructure, chemical composition, and wear resistance of the cladding coating were revealed by optical microscope (OM), scanning electron microscope(SEM), energy-dispersive x-ray analysis (EDX) and sliding wear machine. The microstructure of the cladding layer was found to consist of three zones: a top cladding zone mainly comprising CoMoCr; an internal zone comprising a cellular microstructure; and the interface zone which was a mixture of CoMoCr and 718H substrate. Compared to the 718H steel substrate with a microhardness of 345?Hv, the microhardness of the cladding coating showed a significant improvement, with its value increasing to 794?Hv. The wear results confirmed that the wear resistance was enhanced after laser cladding CoMoCr alloy powder.     

热作模具钢表面激光熔覆Stellite X-40钴基合金

利用2KWCO2连续激光在H13热作模具钢表面熔覆Steun X-40钴基合金,选择最佳的交互作用时间进行激光熔覆处理,可获得均匀细小的熔覆层组织。采用光学显微镜、扫描电子显微镜,X射线衍射仪、磨损试验机及动电位极化技术对熔覆层的组织结构、元素分布、磨损性能及电化学腐蚀性能进行了系统研究：结果表明,H13热作模具钢经激光熔覆SteuiteX-40钴基合金后,其抗磨损及腐蚀性能得到明显改善,经生产实际应用寿命考核,采用激光熔覆处理的H13钢模具,使用寿命提高3倍以上。     

45钢电子束扫描表面W合金化组织和硬度

电子束扫描表面合金化技术可以改善钢铁材料的组织及性能. 采用等离子热喷涂技术和电子束扫描技术对45钢表面进行熔覆合金化处理. 研究电子束扫描对强化层组织和硬度的影响,探讨了电子束功率、扫描速度对强化层组织和硬度的影响规律. 结果表明,45钢经表面合金化处理后,其表面可分为合金化区、热影响区和基体区. 合金化区的显微组织为针状马氏体和碳化钨颗粒,硬度为1 250 HV,是基体硬度的5倍. 热影响区的组织为针状马氏体和铁素体,硬度为860 HV,是基体的3倍. 基体区的组织为珠光体和铁素体. 电子束工艺参数对强化层组织和硬度有较大影响,强化层厚度随电子束功率的增加而增大,随着扫描速度的增加而减小.     

Microstructure and wear resistance of Fe-based and Co-based coating of AISI H13

Fe-based and Co-based cladding layers were prepared on the surface of AISI H13 hot die steel by laser cladding technology. The microstructure, hardness and abrasion resistance of the two cladding layers were studied by means of optical microscope, scanning electron microscope, rockwell hardness tester, and high temperature friction and wear tester. Also, the red hardness of the cladding layers was measured, after holding the layers at 600 ℃ for 1 hour by muffle furnace and repeated 4 times. The rockwell hardness values of the substrate, the Fe-based and the Co-based alloy coating measured were HRC 47, HRC 52 and HRC 48, respectively. The red hardness values of the substrate and the Fe-based cladding layer were decreased, while that of the Co-based cladding layer was increased. The Co-based cladding layer has the minimal wear loss weight and friction coefficient among them. The wear mechanisms of the substrate, the Fe-based layer and the Cobased layer attribute mainly to abrasive wear, adhesion wear, and both of them, respectively.     

Surface modification of Al-Pb alloy by high current pulsed electron beam

Al-Pb alloy was modified by high current pulsed electron beam and the microstructure, hardness and tribological characteristics were characterized by scanning electron microscopy, electronic microanalysis probe microanalysis, Knoop hardness indentation and pin-on-disc type wear testing machine. The results show that the microstructure and hardness can be greatly improved, and the modification layer consists of a molten zone, an overlapped zone of heat-affected and quasistatic thermal stress-affected zone and a transition zone followed by the substrate. The tribological properties of high current pulsed electron beam irradiated Al-Pb alloy are correspondingly improved largely. Optical observation and scanning electron microscopy analysis reveal that the low wear rate and lowest level in coefficient of friction at high load level for irradiated Al-Pb alloy are due to the formation of a lubricious tribolayer covering the worn surface, which is a mixture of Al2O3, Pb3O4 and silicate. The wear mode varies from oxidative wear at low load to film spalling at high load and, finally, adhesive wear.     

激光熔化沉积修复40CrNiMoA高强钢的组织与性能

采用激光熔化沉积技术对40CrNiMoA高强钢表面进行沉积修复，利用光学显微镜、扫描电镜、显微硬度仪和周期浸润腐蚀试验，对40CrNiMoA高强钢基体及其修复区的微观组织、显微硬度和耐腐蚀性能进行研究。结果表明:经激光熔化沉积高Co-Ni二次沉淀硬化合金钢修复后，40CrNiMoA高强钢表面的耐磨损和耐腐蚀性能得到显著提高。修复区组织是由C元素过饱和的铁素体、残余奥氏体、M₃C渗碳体和M₂C型碳化物组成；热影响区组织由最初的回火索氏体转变为片状马氏体。     

激光熔覆Al0.1CoCrFeNi高熵合金涂层的组织和性能

采用激光熔覆技术在H13钢表面制备了Al_0.1CoCrFeNi高熵合金涂层。结果表明,涂层具有单相FCC结构,涂层与基材结合处组织为柱状晶,其他区域为等轴晶;涂层截面显微硬度最高可达560.2 HV0.5,约为基体硬度的2.5倍。涂层表现出明显优于基材的抗热冲击性能。在600 ℃和800 ℃下分别循环50次后涂层均未产生裂纹,但是在1000 ℃高温下循环7次后,基体断裂,而涂层及涂层与基体结合处并没有明显的裂纹。涂层的摩擦因数和磨损率均低于基材,分析表明涂层以氧化磨损为主,而基材的磨损机理为氧化磨损伴随疲劳磨损的混合机制。