nc-(Ti,Al)(C,N)/a-SiNx纳米复合薄膜的制备及性能研究

目的 研究Si、C单元素掺杂及其共同掺杂TiAlN涂层对涂层性能的影响.方法 基于阴极电弧+辉光放电技术,在SUS304不锈钢基体及硬质合金刀具上分别制备nc-(Ti,Al)N、nc-(Ti,Al)N/a-SiNx、nc-TiAlCN及nc-TiAlCN/a-SiNx/a-C纳米复合薄膜,通过SEM观察涂层的微观组织形貌,并借助EDS表征涂层的元素成分,用XRD分析涂层的物相构成,探究C、Si元素对涂层生长的影响.采用纳米硬度仪测试涂层的硬度,采用二维轮廓仪及三维形貌仪表征涂层的表面粗糙度及表面形貌,通过滑动摩擦磨损试验测定涂层的耐磨性,用纳米划痕仪表征涂层的摩擦系数及涂层与基体的结合强度,用铣削实验表征涂层的切削性能.结果 该技术制备的TiAlN涂层,内部晶相结构复杂,硬度为29.57 GPa,主要归因于Ti2AlN、Ti2N等硬质相及TiN0.3相的形成降低了涂层的晶格常数.此为首次报道通过物理气相沉积方法制备含TiN0.3相的涂层.TiAlSiN涂层的硬度最高,为37.69 GPa,且耐磨性最好,主要原因是Si的添加起到了细晶强化和晶界强化的作用.C掺杂TiAlN使涂层析出更多非晶相,涂层硬度降低.C、Si元素共同掺杂,使得nc-TiAlCN/a-SiNx/a-C涂层表现出较低的摩擦系数及表面粗糙度,但与基体的结合性能最差,nc-(Ti,Al)N/a-SiNx薄膜的结合强度最好.结论 涂层均提高了基体表面的显微硬度,Si、C元素的掺杂可使涂层的某些性能得以大幅提升,但在实际应用中,还需根据应用需求选择合适的涂层.     

铝基非晶纳米晶复合涂层研究

采用自动化高速电弧喷涂系统,用自行研制的粉芯丝材,在AZ91镁合金基体表面上制备出Al-Ni-Y-Co非晶纳米晶复合涂层.采用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、透射电子显微镜(TEM)分析了Al-Ni-Y-Co非晶纳米晶复合涂层的微观形貌和组织结构,结果表明Al-Ni-Y-Co非晶纳米晶复合涂层是由非晶相和纳米晶化相共同组成的,涂层结构致密,孔隙率约为1.8%.Al-Ni-Y-Co非晶纳米晶复合涂层的平均显微Vickers硬度值为311.7 HV0 1,结合强度为26.8 MPa.涂层的抗磨损耐腐蚀性能优于Al涂层和AZ91镁合金基体;其相对耐磨性约为Al涂层的10倍,为AZ91镁合金的6倍;其自腐蚀电位值正于Al涂层及AZ91镁合金,自腐蚀电流密度值约为Al涂层的1/2,AZ91镁合金的1/5;其腐蚀后的表面形貌比Al涂层和AZ91镁合金平整,点蚀较少.Al-Ni-Y-Co非晶纳米晶复合涂层的耐磨防腐综合性能优异.     

激光原位制备TiN/Al复合涂层及其抗冲蚀性能

表面处理是提高钛合金抗冲蚀性能的重要途径。采用激光氮化涂层过程中同步送Al粉的方法,在Ti6Al4V合金表面制备了一层均匀的TiN/Al复合涂层,涂层内没有微观裂纹和孔洞。研究结果表明:激光扫描速度对复合涂层的微观结构、硬度及抗冲蚀性能有着重要的影响。随着激光扫描速度的增加,复合涂层的厚度降低。在复合涂层最表面存在一层平均厚度大约为2~3μm的连续的氮化物陶瓷层,涂层内部存有大量的枝状晶组织。复合涂层的微观硬度和抗冲蚀性能明显高于Ti6Al4V合金基体。当激光扫描速度从240 mm/min升高到720 mm/min时,涂层表面的微观硬度从1 600 HV_(0.1)降低到1 200 HV_(0.1),而且涂层的冲蚀失重也逐渐降低。这主要是因为随着激光扫描速度的降低,由于反应时间的增加,导致涂层中TiN硬质相的含量也在增加。     

高速电弧喷涂铝基非晶纳米晶复合涂层的组织及性能

采用自动化高速电弧喷涂系统,将自行研制的粉芯丝材在AZ91镁合金基体表面制备出2种Al基非晶纳米晶复合涂层。采用扫描电子显微镜(SEM)观察非晶纳米晶复合涂层横截面的微观形貌,利用XRD对非晶纳米晶复合涂层进行结构分析。结果表明,非晶纳米晶复合涂层是由非晶相和晶化相共同组成,涂层致密,孔隙少。Al-Ni-Y-Co涂层的维氏硬度值为3117.6MPa,Al-Ni-Mm-Fe涂层的维氏硬度值为3407.2MPa,约为传统Al-RE涂层的4倍左右,为AZ91镁合金基体的5倍左右。电化学试验结果表明,Al-Ni-Y-Co、Al-Ni-Mm-Fe涂层的耐蚀性优于传统Al-RE涂层和AZ91镁合金基体。     

高速电弧喷涂铝基非晶纳米晶复合涂层的组织及性能

采用自动化高速电弧喷涂系统,将自行研制的粉芯丝材在AZ91镁合金基体表面制备出2种Al基非晶纳米晶复合涂层。采用扫描电子显微镜（SEM）观察非晶纳米晶复合涂层横截面的微观形貌,利用XRD对非晶纳米晶复合涂层进行结构分析。结果表明,非晶纳米晶复合涂层是由非晶相和晶化相共同组成,涂层致密,孔隙少。Al-Ni-Y-Co涂层的维氏硬度值为3117.6 MPa, Al-Ni-Mm-Fe涂层的维氏硬度值为3407.2 MPa,约为传统Al-RE涂层的4倍左右,为AZ91镁合金基体的5倍左右。电化学试验结果表明,Al-Ni-Y-Co、Al-Ni-Mm-Fe涂层的耐蚀性优于传统Al-RE涂层和AZ91镁合金基体。     

医用钛合金表面纳米晶TiN梯度涂层的显微组织及腐蚀磨损性能（英文）

采用磁控溅射方法在Ti6Al4V钛合金表面制备纳米晶TiN梯度涂层,研究涂层的显微组织和力学性能,并对涂层和Ti6Al4V合金基体在生理环境中的电化学腐蚀行为和腐蚀磨损性能进行比较。结果表明:纳米晶TiN的梯度分布有利于释放涂层中的内应力,使粘附强度增加到90 N。致密的结构和细化的晶粒使涂层表面纳米硬度达到28.5 GPa,纳米晶TiN涂层的防腐蚀效率达到96.6%。与Ti6Al4V合金基体相比,纳米晶TiN涂层的耐腐蚀磨损性能提高了100倍。纳米晶TiN梯度涂层具有良好的化学稳定性和较高的H~3/E~2比(H为硬度,E为弹性模量),是改善耐腐蚀性能和抗磨损性能的主要原因。     

等离子喷涂钼基非晶-纳米晶复合涂层的组织与性能

一种多元素钼基非晶-纳米晶合金粉末(含C、Si、B、Cr、Fe、Ni、Mo等)作为喷涂材料,用大气等离子喷涂在316L不锈钢基体上制备涂层,用X射线衍射仪、扫描电镜、透射电镜、显微硬度仪分析测量涂层的组织和性能,并用谢乐公式计算晶粒尺寸。结果表明：所制备的涂层均匀致密,涂层含有非晶和纳米晶,颗粒尺寸为10～50nm;这种非晶纳米晶复合涂层的硬度和弹性模量分别高达1055HV和214．40GPa。     

铁基非晶纳米晶涂层组织及耐冲蚀性能的研究

利用高速电弧喷涂技术制备FeCrBSiMnNbY系非晶纳米晶涂层.采用扫描电镜、透射电镜和X射线衍射仪等对涂层的组织结构进行表征,着重分析非晶纳米晶的形成机制,并对涂层的高温耐冲蚀性能进行研究.结果表明:涂层的组织主要由非晶相和α(Fe,Cr)相纳米晶组成;其结构致密,组织均匀,孔隙率低,为1.7%;非晶纳米晶涂层具有良好的耐高温冲蚀性能,攻角增加,涂层冲蚀率随之增加;冲蚀温度升高,涂层耐冲蚀性能也随着提高.     

Si和Y掺杂对(Ti,Al)N涂层结构和性能的影响

分别在未施加偏压和施加-100 V偏压条件下,利用磁控溅射技术在压气机叶片用1Cr11Ni2W2MoV热强不锈钢基体上沉积了Ti_0.3Al_0.7N和Ti_0.39Al_0.55Si_0.05Y_0.01N硬质涂层.实验结果表明,施加偏压及Si和Y掺杂明显改变了涂层的相结构,提高了涂层致密度,施加-100 V偏压且添加Si和Y的涂层为非晶结构,表面更加均匀致密.950℃氧化实验表明:Ti_0.39Al_0.55Si_0.05Y_0.01N涂层表面形成极薄且致密的Al₂O₃保护性氧化膜,大大降低了氧化速率.施加-100 V偏压的（Ti,Al）N和（Ti,Al,Si,Y）N沉积态涂层与未施加偏压的相应涂层相比,硬度均降低,尤其是（Ti,Al,Si,Y）N涂层变化显著.经950℃热处理,施加偏压的（Ti,Al,Si,Y）N涂层硬度略有降低,这是由于形成了硬度较低的B4相,而未施加偏压的（Ti,Al,Si,Y）N涂层硬度显著提高,这归因于B1相固溶体的分解.划痕测试结果表明,在实验载荷（50N）下,所有涂层均未出现连续性的剥落.     

多弧离子镀法制备TiAlNC涂层的微观结构

在碳化钨硬质合金WC-6%Co基体上采用多弧离子镀技术制备Ti Al NC涂层,采用扫描电镜和透射电镜观察涂层的微观组织结构,采用X射线衍射仪和X射线能谱分析仪分别确定涂层的物相及其化学成分。实验结果表明:涂层表面粗糙但均匀连续,且表面出现孔隙和少量的微裂纹;涂层与基体结合较好,无分层现象出现,其沉积速率约4.5μm/h。涂层的平均化学组成为Ti(20±9 at%),Al(16±5 at%),N(39±5 at%)和C(25±10 at%),涂层由纳米晶Ti N和非晶(Ti,Al)(N,C)两物相组成。     

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.     

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.     

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.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.