铬锆铜表面等离子喷涂Cr3C2p/NiCr涂层的组织与性能

采用等离子喷涂技术在铬锆铜(CrZrCu)基体表面制备了Cr3C2 p/NiCr涂层。利用X射线衍射仪(XRD)、扫描电镜(SEM)等仪器研究了涂层的显微组织及结构,采用磨粒磨损试验机对Cr3C2 p/NiCr涂层与电镀NiCo层的磨损性能进行了测试比较。结果表明:涂层组织呈片层状结构,在NiCr合金片层上分布着未熔的Cr3C2和Cr7C3、Cr2Ni3、CrNi析出相。与电镀Ni-Co镀层相比,Cr3C2 p/NiCr涂层具有较高的硬度和耐磨粒磨损性能,其磨损量仅为电镀层的35%。     

超音速火焰喷涂Cr3C2/NiCr涂层抗加沙空蚀性分析

采用HVOF技术在1Cr18Ni9Ti不锈钢基体上制备了Cr3C2/NiCr涂层,借助XRD,TEM,SEM等方法分析了涂层的组织形貌及相组成.以1Cr18Ni9Ti奥氏体不锈钢作为对比材料,用磁致伸缩空蚀仪配备扬沙装置测试了涂层在清水以及含沙水中抗空蚀性能.结果表明,涂层呈层状结构,含有未熔颗粒和少量孔隙,涂层由Cr3C2,Cr7C3,Cr23C6及NiCr等相组成;在清水试验中,1Cr18Ni9Ti不锈钢抗空蚀性能良好,与空蚀过程中1Cr18Ni9Ti奥氏体不锈钢产生加工硬化有直接关系;在含沙40 kg/m3试验水中,Cr3C2/NiCr涂层呈现出较好的抗空蚀性能,与涂层自身相组成以及较高硬度有关.Cr3C2/NiCr涂层破坏总是从孔隙等薄弱环节开始,而1Cr18Ni9Ti奥氏体不锈钢的破坏起始于晶界和孪晶界.     

球扁钢用铸铁轧辊表面等离子喷涂Cr3C2-25NiCr涂层工艺优化

以球扁钢轧制用铸铁轧辊的表面强化为目的,对等离子喷涂Cr3C2-25NiCr涂层工艺进行了研究.结果表明,影响涂层强度的因素依次为功率、喷涂距离、主气流量和送粉速率,Cr3C2-25NiCr涂层最佳工艺参数是喷涂距离130 mm,主气流量69.8 L/min-1,送粉速率25 g/min,功率20 kW.采用优化后的等离子喷涂工艺制备的涂层,呈典型的层状结构,粒子熔化充分,组织致密,孔隙率低,与基体结合较紧密.     

激光熔覆制备NiCr/Cr3C2-WS2-CaF2复合材料涂层

以NiCr/Cr3C2-WS2-CaF2复合合金粉末为原料,采用激光熔覆技术,在1Cr18Ni9Ti不锈钢表面制备了高温自润滑耐磨复合材料涂层。采用XRD、SEM和EDS等手段对所制备复合涂层的显微组织进行了分析,并分别测试了涂层在室温、300℃、600℃时的干滑动磨损性能。结果表明:该复合涂层由γ-(Ni,Fe)固溶体基体、Cr7 C3/WC增强相及CrS/WS2润滑颗粒组成;室温时,涂层的磨损率较大;随着温度的升高,由于润滑转移膜的形成,涂层拥有良好的减摩耐磨性能。     

热喷涂NiCr/Cr3C2、NiCrCoAlY、涂层的微观组织结构及抗震性能

研究分析了等离子喷涂NiCr／Cr3C2、NiCrCoAlY涂层的微观组织结构，并对2种涂层进行了显微硬度及抗热震性能实验。结果表明：NiCr／Cr3C2涂层的硬度高于NiCrCoAlY涂层．而NiCrCoAlY涂层的抗热震性能优于NiCr／Cr3C2涂层。     

WC增强镍基复合喷焊层的组织与磨粒磨损性能研究

采用扫描电镜、电子探针、X射线衍射和透射电镜技术分析了氧乙炔火焰喷焊WC增强镍基自熔性合金复合涂层的组织结构,并采用湿砂橡胶轮式磨粒磨损试验机对该涂层与等离子喷涂NiCr/Cr3C2涂层的磨损性能进行了实验比较.结果表明,复合喷焊层内形成了γ-Ni固溶体基体,其中弥散分布着大量细小的碳化物硬质相Cr3C2、B4C、Cr7C3、Cr23C6等.WC颗粒仅在边缘处发生部分溶解,与涂层基体形成了冶金结合,周围生成针状的碳化铬枝晶.该组织决定了喷焊层基体具有较高的硬度,WC增强颗粒与基体之间具有很高的结合强度.复合喷焊层具有很好的耐磨粒磨损性能,其磨损失重量仅为NiCr/Cr3C2涂层的57%.     

超音速火焰喷涂Cr_3C_2-25NiCr涂层的制备工艺及组织研究

利用超音速火焰喷涂技术在结晶器铜板表面喷涂Cr3C2-25NiCr涂层,采用正交试验设计研究了不同工艺参数对涂层孔隙率的影响,并对涂层的表面、截面形貌和粉末及涂层的相组成等进行分析。研究结果发现,在喷涂过程中,Cr3C2-25NiCr涂层发生了不同程度的分解和氧化,而且喷涂距离对孔隙率的影响最大。本试验获得的最佳工艺参数为氧气流量900L/min,煤油流量6.0g/h,喷涂距离375mm,涂层厚度0.4mm,经过工艺优化后制备的Cr3C2-25NiCr涂层组织均匀致密,与基材结合良好,孔隙率较低。     

CuCrZr合金表面等离子喷涂Cr3C2-NiCr及NiAl/Cr3C2-NiCr涂层的结合性能

在CuCrZr合金表面等离子喷涂Cr3C2-NiCr涂层、NiAl/Cr3C2-NiCr复合涂层.测试涂层与基体间的结合强度及涂层的热震性能,结合SEM,EDS和XRD等分析涂层物相变化,探讨涂层的结合机理.结果表明,涂层的结合强度均较高;Ni-Al发生放热反应,生成Al4Ni3,Al3Ni2,AlNi3,剩余的铝与铜反应生成Cu3Al2,CuAl2,CuAl,局部区域形成微冶金结合;二种涂层均以机械锚合为主,在参数适合且基体相同的情况下,涂层结合强度取决于涂层材料的力学性能;相同试验条件下,NiAl/Cr3C2-NiCr复合涂层的热震性能优于Cr3C2-NiCr涂层.     

在H13钢上超音速火焰喷涂制备WC-10Co-4Cr和Cr_3C_2-25NiCr涂层的性能比较（英文）

在H13钢基体上采用超音速火焰喷涂方式制备一定厚度的WC-10Co-4Cr和Cr_3C_2-25NiCr涂层。为了增加WC-10Co-4Cr涂层的热稳定性,在涂层和基体之间加喷了NiCr喷涂粉末。研究了这两种硬质合金涂层的表面及横截面的微观形貌、抗热震性和耐磨损性能。从热力学的角度解释了两种涂层中出现的碳扩散现象。Cr_3C_2-25NiCr涂层的结合强度(64.40 MPa)和WC-10Co-4Cr涂层的结合强度(61.69 MPa)基本相同。通过摩擦磨损试验研究发现,两种涂层在600℃的摩擦因数均比在500℃时的小,Cr_3C_2-25NiCr的耐磨损性能比WC-10Co-4Cr的要好。     

不同(Mo+B)/(Ni+Cr)质量比的原位合成MoB/NiCr涂层的组织结构与性能

采用超音速火焰喷涂技术沉积含3种不同(Mo+B)/(Ni+Cr)质量比（1:1,2:1和3:1）的Mo-B-Ni-Cr球磨复合粉末以原位反应制备获得MoB/NiCr涂层。采用扫描电子显微镜（SEM）和X射线衍射仪（XRD）分析了MoB/NiCr涂层的组织结构和物相。同时讨论了不同(Mo+B)/(Ni+Cr)质量比对涂层的组织结构、硬度、结合强度和耐腐蚀性能的影响。研究结果表明,(Mo+B)/(Ni+Cr)质量比为1：1的MoB/NiCr涂层孔隙率最低及涂层厚度最大。在3种涂层中均原位反应生成了Mo₂NiB₂三元硼化物,且随着(Mo+B)/(Ni+Cr)质量比的增加,涂层中三元硼化物含量随之增加,涂层的硬度值增加,结合强度反而随之降低;由于涂层中三元硼化物的原位生成,MoB/NiCr涂层的硬度值均高于316L不锈钢基体。通过能谱和XRD分析发现,经过360 h熔融锌腐蚀试验后,涂层表层中没有发现锌元素及其金属间化合物,然而随着(Mo+B)/(Ni+Cr)质量比的增加,涂层的孔隙率增加及厚度降低。最后,综合分析可得,相比其他涂层,(Mo+B)/(Ni+Cr)质量比为1:1的MoB/NiCr涂层具有更好的耐熔融锌腐蚀能力。     

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.     

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。     

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.     

THERMODYNAMICS STUDY ON THE DECOMPOSITION OF CHROMITE WITH KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

INFLUENCE OF HEAT TREATMENT ON DAMPING BEHAVIOUR OF THE MAGNESIUM WROUGHT ALLOY AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

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.     

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.     

High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite

A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.