高速电弧喷涂FeAlCr涂层的组织与耐磨性研究

为了提高Fe-Al金属间化合物涂层的结合强度和耐磨性,改善其室温韧性,研制了一种新型FeAlCr电弧喷涂粉芯丝材,利用高速电弧喷涂技术在45#钢基体表面制备了涂层。采用扫描电镜(SEM)、能谱仪(EDAX)和X射线衍射仪分析了涂层的微观结构和微区成分,用显微硬度计、拉伸试验机和CETR微动摩擦磨损试验机等试验设备对涂层的力学性能进行了分析。结果表明,喷涂FeAlCr粉芯丝材过程中合金元素反应充分,涂层组织均匀、致密,氧化物含量极低。主要相组成有Fe-Al、Ni3Al金属间化合物,硬质相Cr3C2、氧化物Cr2O3和Al2O3弥散分布在韧性相α-Fe基体上。涂层平均HV显微硬度为5.50 GPa,约是基体的2倍,平均结合强度约47.2 MPa,载荷100 N油润滑条件下涂层的耐磨性高于基体,磨损率随着摩擦过程的进行呈降低趋势。     

微粒轰击Fe基非晶电弧喷涂层性能强化

为了减小热喷涂层残余应力对涂层质量的不利影响,采用喷丸(砂)微粒轰击与高速电弧喷涂相互循环交替的工艺制备了Fe基非晶涂层,使涂层残余拉应力变为残余压应力,喷丸(砂)强化涂层表面残余应力由未处理涂层表面残余拉应力277 MPa分别变为残余压应力-177 MPa(-91 MPa)。利用电子扫描显微镜、纳米压痕仪、摩擦磨损试验机等分别对涂层的微观形貌、力学性能和摩擦磨损性能进行了测试。结果表明:经过微粒轰击后的涂层表面致密平整,组织结构密实,喷丸(砂)强化涂层的孔隙率仅为1.0%(1.5%),结合强度可达44.6 MPa(56.4 MPa),经过微粒轰击后涂层硬度、弹性模量及摩擦磨损性能都有所提升。喷丸强化涂层局部过度的轰击会使涂层结合强度及摩擦磨损性能略有下降。     

爆炸喷涂WC-Co/CoMoCrSi复合涂层的组织与性能

为了提高CoMoCrSi涂层的结合强度和力学性能,采用爆炸喷涂技术制备了WC-12Co涂层作为过渡层的WC-Co/CoMoCrSi复合涂层,借助SEM和EDS等手段分析了涂层截面组织形貌和化学元素组成,采用显微硬度计、万能拉伸机及销盘式摩擦磨损试验机等研究了涂层的力学及摩擦磨损性能。结果表明：在氧燃充枪比为60%的喷涂参数下,制备WC-Co/CoMoCrSi复合涂层平均结合强度高达66 MPa,涂层截面组织致密、均匀,孔隙率小于0.6%,平均显微硬度为667 HV0.1,复合涂层摩擦因数0.53~0.56,具有优异的耐磨性能。     

高速电弧喷涂FeCrAl/Ni95Al复合涂层的性能

利用电弧喷涂技术在45钢基体表面制备了FeCrAl/Ni95 Al复合涂层,先喷涂Ni95Al打底层增强涂层的结合强度,FeCrAl涂层作为工作层.利用扫描电镜(SEM)、能谱仪(EDS)、X射线衍射仪、拉伸试验机、显微硬度计和CETR微动摩擦磨损试验机研究了涂层的显微组织、力学性能及摩擦磨损性能.结果表明,复合涂层组织均匀致密,主要由Fe3Al金属间化合物、(Fe,Cr)固溶在涂层基体中.涂层结合强度为43 MPa,硬度值为530 HVO.1,涂层磨损失效形式为剥落和氧化磨损.     

冷喷涂对2219铝合金搅拌摩擦焊接头残余应力与力学性能的影响

为了改善铝合金搅拌摩擦焊接头残余应力与力学性能,在4 mm厚2219铝合金搅拌摩擦焊接头上表面进行冷喷涂试验,研究分析了冷喷涂前后接头残余应力与力学性能的变化. 结果表明,焊态接头纵向残余应力呈不对称“M”形分布,残余应力峰值位于前进侧靠轴肩附近;冷喷涂后,接头残余应力大幅度降低,残余应力峰值由186 MPa降低至43 MPa.涂层沉积厚度约200 μm,涂层与基体界面产生了较大的塑性变形,基体界面附近组织晶粒得以细化.由于冷喷涂过程的喷丸效应,接头上表面显微硬度平均提高了25 HV,作用深度约1 mm.接头拉伸性能也获得明显改善,抗拉强度提升6.3%,断后伸长率提升78.6%,焊态与冷喷涂态的拉伸试样均在接头前进侧的热影响区附近发生断裂,符合在低硬度区或弱结合面产生裂纹并扩展的弱区断裂的特征.     

退火热处理对Cr3C2-FeCrBSi涂层摩擦磨损性能的影响

目的 针对冷轧辊表面的循环应力、摩擦磨损的特殊服役环境,设计空气燃料超音速火焰喷涂(HVAF)制备Cr3C2-FeCrBSi复合涂层来提高工件表面的硬度和耐磨性。方法 利用HVAF技术在冷轧辊用合金钢板表面制备不同尺寸陶瓷颗粒混合的Cr3C2-FeCrBSi的复合涂层,并在600、700、800 ℃进行退火处理后得到退火态涂层。利用XRD、SEM、显微硬度计、电子拉伸试验机、盘式摩擦磨损试验机和接触疲劳试验机,考察了不同陶瓷含量和不同退火温度下涂层的相组成、组织结构、机械性能、摩擦磨损性能和接触疲劳失效形式。结果 喷涂态涂层的显微硬度、结合强度随着Cr3C2含量的增加先上升后下降。当陶瓷相质量分数为10%时,复合涂层最佳,显微硬度、结合强度分别为459.6HV0.3、42.8 MPa。选取Cr3C2(质量分数10%)-FeCrBSi涂层经过退火处理后,涂层的硬度、断裂韧性、抗磨损性能均有提升,其中摩擦因数由原先的0.89降低至0.80~0.75。此外在700 ℃下退火3 h得到的涂层,显微硬度可达490.3HV0.3,断裂韧性由2.81 MPa∙m^1/2提升至3.15 MPa∙m^1/2,磨损率为6.80×10^‒14 m³/(N.m),与喷涂态涂层相比,磨损率降低了15%。喷涂态、退火态涂层的磨损机制均为磨粒磨损。接触疲劳试验结果表明,退火态复合涂层的接触疲劳失效形式主要有剥落和分层,同时剥落失效情况下涂层的接触疲劳寿命更长,可达2.07×10⁵转。结论 Cr3C2-FeCrBSi复合涂层良好的抗磨损和耐接触疲劳性能主要取决于Cr3C2硬质耐磨颗粒的加入。而退火热处理可以促进涂层向平衡态的转变、同时析出的二次碳化物(Cr, Fe)7C3起到沉淀强化的作用,使得退火态涂层具有更好的抗摩擦磨损性能。     

高速电弧喷涂FeAlCr/Ni包Cr3C2复合涂层摩擦学特性

使用THT07-135高温磨损实验机对高速电弧喷涂FeAl,Fe-Al/Cr3C2,FeAlCr/Ni包Cr3C2复合涂层进行了滑动摩擦特性的研究,并用SEM、TEM、XRD等手段观察分析了磨痕的形貌和成分、涂层截面的组织和相结构.结果表明:FeAlCr/Ni包Cr3C2复合涂层具有典型的层状结构和较高的结合强度和硬度;从室温到250℃,涂层的抗磨损性能下降;从250℃到550℃,涂层磨损性能变化不大;550℃以后,涂层的耐磨损性能重新增强;剥层磨损是FeAlCr/Ni包Cr3C2涂层高温磨损的主要机理;Cr3C2增强相的加入,大大提高了涂层的耐磨损性能;Ni的加入一定程度提高了涂层的结合强度和抗磨损性能.     

不同燃料超音速火焰喷涂NiCr-Cr3C2涂层

采用超音速火焰喷涂工艺在20CrMo钢圆片上成功制备25%NiCr-Cr3C2金属陶瓷涂层,研究了不同燃料对喷涂层组织性能的影响。结果表明,以丙烷为主要燃料所得喷涂层的组织不均匀,存在典型的层状结构,孔隙率约为3.2%,显微硬度仅为836 HV,涂层断裂韧性KIC为2.08 MPa.m3/2;以煤油为主要燃料所得喷涂层的组织分布均匀,细小致密,孔隙率约为2.4%,显微硬度可达1045 HV,涂层断裂韧性KIC为2.56 MPa.m3/2。前者的组成相为Ni(Cr)固溶体、Cr3C2和微量NiCrO4;后者的组成相除Ni(Cr)固溶体和Cr3C2外,还有Cr7C3、Cr23C6和Ni(Cr)相出现。     

CNTs含量对微弧等离子喷涂CNTs/AT40涂层力学性能的影响

采用微弧等离子喷涂成功制备了CNTs/Al_2O_3-40%TiO_2复合吸波涂层,借助扫描电镜、X射线衍射仪、拉伸试验机、显微硬度计等测试手段,对涂层的组织结构、结合强度、显微硬度和热震性能进行了测试分析。结果表明:涂层组织结构致密,孔隙率低;CNTs的含量对复合涂层的力学性能有较大影响,随CNTs含量的增加,CNTs/AT40复合涂层的结合强度、显微硬度和热震性能都先增大后减小。CNTs质量分数为3%时,平均结合强度最高,厚度0.5 mm时结合强度为32.08 MPa,比AT40涂层的结合强度24.09 MPa提高了33.2%,平均显微硬度为821.6 HV0.1,比AT40涂层提高了20.4%,厚度2.0 mm时热震次数为63次,比AT40涂层增加了16%。     

热处理对10%Ni-AT13涂层摩擦磨损性能的影响北大核心CSCD

采用等离子喷涂技术在45钢基体上制备10%Ni-AT13复合涂层,利用QG-700型球-盘式摩擦磨损试验机在室温干摩擦条件下对其进行了摩擦磨损试验;利用显微硬度计、万能拉伸试验机、扫描电镜(SEM)及X射线衍射仪(XRD)等对涂层的力学性能、微观组织进行了表征分析,并研究了去应力退火(300℃保温3 h)对10%Ni-AT13涂层性能的影响。结果表明:涂层呈典型的层片状结构分布,由熔融区和半熔区组成,涂层与基体之间的结合良好;XRD结果显示涂层有新相Al_2TiO_5和Ni_2O_3生成,退火对涂层的组织成分无影响;与退火前相比,涂层的力学性能得到明显的提高,其中结合强度提高了78.7%、显微硬度提高了43.6%、断裂韧性提高了64.1%;退火后,在摩擦过程中摩擦系数高低变化不大,但波动性减小;涂层的磨损率比退火前小,耐磨性得到了提高。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

The Mirror with Patterns of Auspicious Animals and Grapes——Exquisite cast mirror and the technology of surface tin-enrichment by rubbing-in and infiltration of tin-rich powder

<正>Bronze mirrors were used by the Chinese people before the introduction of the glass mirror.Only after it was replaced by the glass mirror did the bronze mirror gradually retreat from people's lives.Different styles of bronze mirrors were made in different historical periods,particularly in the Warring States Period,the Han and Tang Dynasties,which were the three peaks of the development of bronze mirror arts in ancient China.The casting techniques were exquisite.The surface of the bronze mirror was smooth and bright enough to reflect one's image,and there were scarcely any casting defects on the mirror surface.On the back of the bronze mirror,there were rich depictions of Arts and Humanities,and the ornamentations were also     

The 9th China International Diecasting Congress & Exhibition

The 9th China International Diecasting Congress ＆ Exhibition was held on July 22-24, 2014 at Shanghai New International Expc Centre. This exhibition was the most successful over the years, with over 6890 visitors and 155 exhibitors, and the exhibition area increased by 30% from 9,500 square meters in 2012 to 12340 square meters. Die casting enterprises from a total of 24 countries and regions, including China mainland, Chinese Taiwan and Hong Kong, South Korea, Japan, Germany, India, Thailand, Malaysia, the United States, Russia, Australia, Iran, Ukraine, Brazil, Colombia, Singapore, Austria, Canada, Croatia, France, Turkey, United Kingdom, Vietnam, attended the congress and exhibition.     

Introduction of the Fluid Control Engineering Institute of Kunming University of Science and Technology

正The Fluid Control Engineering Institute of Kunming University of Science and Technology was set up in 1996.The researches of institute concentrate on electro-hydraulic(pneumatic)servo/proportional control and hydromechatronics.The Institute is committed to research and development of electro-hydraulic control of high-end technical equipment in ferrous metallurgy refining produc-     

RARE METALS Volume Contents

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