网状陶瓷复合材料的滑动磨损行为

研究了三维连续网状多孔陶瓷复合材料在干摩擦条件下的滑动磨损行为。结果表明：复合材料的耐磨性优于基体合金;复合材料对磨环的磨损量大于基体合金对磨环的磨损量,但复合材料摩擦副的总磨损量比基体合金摩擦副的小。     

三维连续镍网增强ZL109复合材料磨损机理研究

采用真空吸铸制备了三维连续镍网增强ZL109复合材料,利用M-200型摩擦磨损试验机对复合材料在干摩擦条件下的磨损行为及磨损机理进行了研究.结果表明,三维连续镍网与基体界面处生成了新相Al3Ni2；复合材料的耐磨性始终优于基体合金,且随着网络孔径的减小,复合材料的的耐磨性增强.在磨损过程中,ZL109为典型的粘着磨损,复合材料为粘着磨损和磨粒磨损同时起作用.     

Al3Ti/7075铝基复合材料磨损性能研究

研究了超声原位制备的Al3 Ti/7075铝基复合材料在不同载荷和滑动摩擦速度下的干摩擦磨损性能.采用SEM对磨损面和磨屑显微组织进行观察与分析,讨论了不同载荷下材料的磨损机制.结果表明:基体和复合材料磨损质量损失随着滑动摩擦速度和载荷的增加而增加.基体和复合材料都是从轻微磨损向严重磨损转化.当载荷为10～30N时,基...     

颗粒级配对SiCp／Al复合材料摩擦磨损性能的影响

采用销-盘摩擦磨损试验机,考察了高体积分数SiCp/Al复合材料中颗粒尺寸及颗粒级配等组织因素对材料干摩擦磨损性能的影响.通过磨损表面的SEM形貌分析,研究了复合材料的磨损机理.结果表明,与灰铸铁配副时,材料的摩擦系数与磨损率明显依赖于碳化硅颗粒尺寸,二者均随颗粒尺寸的增大而先降低后增大.采用颗粒级配方法能明显改善复合材料的干摩擦磨损性能.粗细颗粒问的级配具有相互强化的作用,有利于降低摩擦系数和磨损率,并使其趋于稳定.复合材料的磨损以对偶件材料的转移和犁沟为特征.     

铸态硅酸铝短纤维／ZL109复合材料的摩擦磨损性能

摩擦磨损试验结果表明,硅酸铝短纤维／ＺＬ１０９复合材料在干、油摩擦条件下,其耐磨性都大大高于基体合金,摩擦系数明显低于基体合金,特别是在干摩擦条件下,耐磨性提高幅度、摩擦系数降低幅度更大。适当的时效能改善复合材料的耐磨性,当处于峰时效时,复合材料的摩擦系数往往较小     

SiC含量对Al/SiC纳米复合材料干滑动磨损、腐蚀以及腐蚀磨损行为的影响（英文）

纳米复合材料的腐蚀、腐蚀磨损以及干摩擦磨损行为非常复杂,受化学、物理和机械等多方面因素影响。采用机械球磨、冷压和热挤压技术制备Al/SiC纳米复合材料,研究纳米SiC含量对材料硬度、干滑动磨损、腐蚀和腐蚀磨损行为的影响。采用电化学极化测试研究了复合材料在3%NaCl溶液中的抗腐蚀性能。采用盘-销装置研究了复合材料的干滑动磨损和在3%NaCl溶液中腐蚀磨损性能。利用扫描电子显微镜研究了材料及磨损表面的显微组织。结果表明,随着SiC含量的增加,纳米复合材料的干滑动摩擦和抗腐蚀性能均得到提高。由于溶液的润滑作用,使材料软化的摩擦因数和摩擦生热均降低。与基体合金相比,纳米复合材料的强度和抗腐蚀性能提高,因此其抗腐蚀磨损性能也提高。对于未增强的基体合金,其磨损机理为黏着磨损,而对于Al/SiC纳米复合材料,磨损机理转变为磨粒磨损。     

锡对铸造铝-石墨颗粒复合材料摩擦性能的影响

采用M-200摩擦磨损试验机,对加入固体润滑剂锡的铸造铝-3%石墨颗粒复合材料的摩擦性能进行试验研究,研究表明:锡和石墨具有优越的协同润滑效应,加锡可极大提高铝-石墨颗粒复合材料的减摩性能,使有润滑的摩擦系数达到0.004～0.005。同时锡和石墨的协同润滑作用存在最佳配合,在本试验条件下,加约7%的锡时,协同润滑效应最佳。加锡不能改善干摩擦时铝-3%石墨颗粒复合材料的耐磨性,但能极大提高有润滑时复合材料的耐磨性。并对加锡的铝-石墨颗粒复合材料的磨损机理进行了初步研究,其在干摩擦时的磨损机理为粘着迁移、粘着磨损和磨料磨损,在半干摩擦时的磨损机理为疲劳磨损和磨料磨损。     

粉煤灰泡沫陶瓷铝基复合材料耐磨性能的研究

从摩擦时的转速、磨损时间、摩擦副的表面粗糙度和载荷等方面研究这些因素对复合材料耐磨性的影响,研究了粉煤灰泡沫陶瓷复合材料及基体材料的抗磨损性能。结果表明,粉煤灰泡沫陶瓷复合材料具有较高的耐磨性,其耐磨性明显高于基体,该复合材料抵抗磨损的性能比基体材料增加了3～4倍。     

硼酸镁晶须增强6061铝基复合材料的干摩擦磨损行为(英文)

研究搅拌铸造工艺制备的硼酸镁晶须增强6061铝基复合材料在干滑动条件下的摩擦磨损性能。复合材料的体积分数为2%,根据增强体种类,材料分别记为:Al基体、Mg2B2O5w/6061Al、ZnO/Mg2B2O5w/6061Al和CuO/Mg2B2O5w/6061Al;讨论磨损速率和摩擦因数之间的关系。结果表明:在4种材料中,ZnO/Mg2B2O5w/6061Al复合材料的磨损率最低。随着载荷和滑动速度的增大,基体和复合材料的摩擦因数和磨损率降低,摩擦磨损机制由轻微磨损机制转向严重磨损机制。     

石墨表面金属化对铜基复合材料摩擦学性能的影响

利用化学镀技术制备镀铜和镀镍石墨粉,采用粉末冶金复压复烧工艺制备铜基石墨自润滑复合材料,测试了复合材料的摩擦磨损性能,利用X射线衍射、扫描电镜和能谱仪等分析该复合材料的结构、摩擦磨损性能及机理。结果表明：石墨表面铜、镍镀层改善了石墨和铜合金基体界面结合,摩擦过程中所形成的润滑膜与基体粘附性好,显示出更好的润滑减摩效果,摩擦副摩擦因数由0.24降低到0.20,磨损率降低约50%;实验条件下,6%（质量分数）石墨铜基复合材料经历轻微磨损、中等磨损和严重磨损3个磨损过程;而6%镀铜、镀镍石墨铜基复合材料只经历轻微磨损和中等磨损两个磨损过程。     

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。     

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.     

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.