SiO_2、Al_2O_3、ZrO_2对磨副材料对离子渗氮工业纯钛TA2磨损性能的影响

研究了离子渗氮处理工业纯钛TA2与硬质材料对磨的磨损性能。采用球盘摩擦磨损试验机评价摩擦学性能,选取了3种硬度的对磨副材料Si O2、Al2O3、Zr O2。利用光学显微镜、白光三维形貌仪、X射线衍射仪和显微硬度计分别对渗氮前后TA2的微观组织结构和硬度进行表征,并分析磨痕的表面形貌及元素组成。结果表明,渗氮后TA2表面生成了80μm厚的Ti N、Ti2N和α-Ti(N)硬质相渗氮层,表面硬度由140 HV提高至1260 HV,耐磨性能得到了提高。未处理样品的磨损机制主要是严重的黏着磨损、塑性形变和一定程度的磨粒磨损;渗氮样品的磨损机制主要为磨粒磨损,磨损率随对磨副材料硬度的升高而增大。     

无氢离子渗氮Ti6Al4V合金摩擦学性能的研究

以纯氮气为气源,在Ti6Al4V合金表面进行离子渗氮而形成渗氮层。对渗氮层的显微组织、相结构及显微硬度等进行了分析,并用MMW-1A摩擦磨损试验机对渗氮层的摩擦学性能进行了研究。结果表明:在纯氮气、850℃的渗氮条件下,渗氮层主要由化合物Ti N、Ti2N和α-Ti等相组成;渗氮层的硬度较基体材料有较大提高;在滑动摩擦磨损试验中,渗氮层虽无减摩效果,但其耐磨性较基材大幅提高;未渗氮处理试样的磨损机理是磨粒磨损和局部的粘着磨损,渗氮后试样的磨损机理是磨粒磨损和局部的疲劳剥落。     

铝合金表面TiN涂层的干摩擦磨损性能研究

采用多弧离子镀技术在铝合金表面沉积了Ti N薄膜。利用球盘摩擦磨损试验仪研究了载荷和转速对Ti N薄膜的摩擦磨损性能的影响。试验以Si3N4为对磨体,磨损半径为5mm,试验环境为室温。结果表明:存在一临界载荷,使得摩擦系数和磨损量产生突变;转速增加,摩擦因数基本不变,但磨合时间有所缩短。利用SEM观察磨痕形貌,对磨损机理进行了分析。随着载荷和转速的增加,Ti N薄膜的磨损机制从轻微粘着磨损逐步向磨粒磨损转变。     

F51双相不锈钢离子渗氮层的组织与性能

目的提高F51双相不锈钢的硬度以及耐磨性能。方法将F51双相不锈钢进行低温(450℃)和高温(550℃)离子渗氮处理,利用光学显微镜(OM)、扫描电子显微镜(SEM)观察F51双相不锈钢渗氮层的微观组织,利用X射线衍射(XRD)方法对渗氮层沿深度方向相组成的变化进行分析,采用显微硬度计、摩擦磨损实验机分别对渗氮层的显微硬度及耐磨性能进行测试,采用激光扫描共聚焦显微镜(LSCM)对磨痕形貌进行观察。结果F51双相不锈钢低温渗氮层主要由N相组成,由表及里为N N+N(少量);高温渗氮层主要由CrN+N相组成,由表及里为CrN+N N+N。高温渗氮层厚度约为低温渗氮层厚度的3倍。低温渗氮样品的平均表面硬度约为基体表面硬度的3.5倍;高温渗氮样品的平均表面硬度约为基体硬度的4倍。基体的摩擦系数约为0.71,低温和高温渗氮处理后样品的摩擦系数大大降低,分别为0.24和0.17。渗氮样品磨痕的宽度和深度较基体显著降低。结论F51双相不锈钢低温渗氮层主要由N相组成,高温渗氮层主要由CrN+N相组成,两种温度渗氮后的样品硬度和耐磨性均得到显著提高。     

AISI304奥氏体不锈钢阳极渗氮层的组织与摩擦磨损性能

为避免传统直流离子渗氮存在的表面打弧和边缘效应等弊端,采用活性屏阳极渗氮法对AISI 304奥氏体不锈钢进行表面处理。将样品放置于阳极电位,在440~520℃范围内,渗氮处理8 h。分析了渗氮层的微观组织结构与形貌,并考察了渗氮前后的摩擦磨损性能。结果表明:在低温440℃下,在表面制备了高硬度的S相强化层。XRD与TEM表明S相为面心立方结构,且无Cr N相析出。高温520℃渗氮表面硬度值(1100 HV0.1)是基体的5倍,但Cr N相明显析出。在干摩擦条件下,渗氮处理后的摩擦系数在0.8左右,相对渗氮前降低约0.2,特别是磨损率只有渗氮前的十分之一量级。磨损机制从原始基体的严重粘着转变为轻微的氧化和磨粒磨损。     

40Cr钢表面渗氮及制备CrN涂层在重载低速下的摩擦学性能

目的提高40Cr齿轮在重载低速下的摩擦学性能。方法采用离子渗氮和电弧离子蒸发镀(AED)技术在40Cr钢基体上制备了渗氮层和Cr N涂层。用X射线衍射仪、扫描电子显微镜、能谱仪和往复式摩擦磨损试验机,研究了经两种表面处理后40Cr钢的物相组成、形貌和摩擦学性能。结果渗氮样品表面化合物层厚度约10μm,硬度约为558HV。Cr N涂层表面厚度约为4μm,涂层硬度约为1341HV。在60 N载荷的条件下,渗氮处理后40Cr钢的磨损率为104.17×10-6 mm3/(N·m),其磨损机理主要为轻微的粘着磨损和磨粒磨损;制备Cr N涂层后40Cr钢的磨损率为17.36×10-6 mm3/(N·m),其磨损机理主要为轻微的磨粒磨损。结论在20~60 N法向载荷下,制备Cr N涂层后,40Cr钢均表现出最优异的耐磨减摩性能。     

高温下TiN涂层的摩擦与磨损行为

采用阴极离子镀方法在YT14硬质合金刀具表面制备了Ti N涂层,用高温摩擦磨损试验机考察Ti N涂层在500℃高温下摩擦-磨损行为。通过扫描电镜观察涂层表面-界面形貌和高温磨损后表面形貌,用XRD分析了Ti N涂层物相变化,并用EDS能谱仪对结合界面进行线扫描分析和磨痕进行面扫描分析,同时用工具显微镜观察了表面犁沟形貌,对Ti N涂层500℃下磨损机理进行探讨。结果表明,Ti N涂层在500℃磨损后发生高温氧化,Ti N涂层表面磨痕处主要以Ti O2为主,这些氧化层起到了润滑减摩的作用,适合于高速切削与干式切削;在5 N载荷作用下,Ti N涂层的摩擦系数平均值为0.7116;在高温下Ti N涂层表现为氧化磨损,同时伴随着一定的磨粒磨损和黏着磨损。     

TA2钛材激光相变增强离子渗氮层的组织与性能

采用激光相变硬化、离子渗氮及激光相变增强离子渗氮3种工艺对TA2钛材进行表面强化处理,并利用X射线衍射仪、扫描电子显微镜、维氏硬度计和摩擦磨损试验机对材料表面硬化层的物相组织、表面形貌、硬度和摩擦学性能进行分析测试。结果表明,激光相变后,试样进行600℃×8 h的离子渗氮可抑制长时间高温渗氮引起的TA2基体组织粗化,获得组织合理、耐磨性能优良的渗氮层。     

激光气体渗氮工艺对TC4钛合金表面性能的影响

钛合金属于粘性材料,易发生粘着磨损,为提高钛合金件作为摩擦副使用时的寿命,需提高钛合金表面硬度及耐磨性。利用连续激光器在TC4合金表面进行激光气体渗氮,生成金黄色的氮化层。用SEM、EDS、XRD分析试样渗氮层的微观组织、元素分布以及物质组成。结果表明,经激光气体渗氮后在TC4表面生成了以Ti N为增强相的改性层,并且在未渗氮区有黑色粉末状Ti N生成。表层由氮化层、热影响区及母材组成。渗氮层与基材发生冶金结合,结合强度高,不易剥落。随着激光功率的提升,渗氮层厚度及硬度都有所增加。当功率为1 200 W时,钛合金表面渗氮层最高硬度超过1 800 HV0.3,渗氮层厚度也最大。在氮气流量为10 L/min时整个渗氮层中氮元素的含量相对较高。经过激光气体表面渗氮后渗氮层的摩擦系数较基体材料摩擦系数有明显降低,耐磨性更好。     

阴极离子镀TiAlSiN涂层高温摩擦与磨损性能

采用阴极离子镀在H13钢表面制备了TiAlSiN涂层,通过扫描电镜、X射线衍射仪、原子力显微镜分析了涂层表面-界面形貌、物相和三维表面微观形貌。利用EDS面扫描分析了磨痕表面化学元素分布,讨论了高温对涂层摩擦磨损性能的影响。结果表明,TiAlSiN涂层表面主要元素由Ti、Al、Si和N组成,主要物相为(Ti,Al)N,未发现Si3N4相;高温氧化后生成的致密氧化膜Al2O3提高了涂层高温抗氧化性,Si O2降低了涂层表面摩擦因数,结构疏松的Ti O2易导致涂层破裂和剥落;TiAlSiN涂层表面粗糙度高于基体表面粗糙度,磨痕表面Ti和Al元素出现贫集区,表明涂层被磨穿;在700、800和900℃下,涂层表面摩擦因数均在0.3左右,在700℃时磨损机制主要为氧化磨损和粘着磨损,在800℃和900℃时主要为氧化磨损,伴随着少量粘着磨损和磨粒磨损。     

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.     

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.     

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.     

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。     

A STUDY OF TEMPERATURE-DEPENDENT VALENCE BOND STRUCTURE OF TITANIUM

On the basis of energy and shape method for the determination of the valence bond (VB) structures of crystal, the valence bond structure of titanium is redetermined at room temperature and calculated in the whole temperature range of 0-1943K. The outer shell electronic distribution of Ti is e_c~(2.9907) · (s_c~(0.4980) d_c~(2.4927)) ef1.0093 in crystal. The temperature dependences of the VB structures of hcp and bcc phases are the same. The VB structures of hcp and bcc phases monotonically increase or decrease with the increase in temperature, but show discontinuous changes at the phase-transformation temperature 1155K.