Ce基含Sn氧化物晶粒长大动力学

采用Pechini法制备了CeO2和17％SnO2-83％CeO2氧化物粉末,研究了该氧化物粉末在不同热处理温度下的晶粒长大规律和生长动力学。结果表明,CeO2粉末的晶体长大过程以400℃为分界点呈现阶段性,小于400℃时的激活能为1．4kJ／mol,大于400℃时的激活能为14．8kJ／mol。17％SnO2-83％CeO2粉末的晶体长大以650℃为分界点,小于650℃时的激活能为9．8kJ／mol,大于650℃时的激活能为90．0kJ／mol。     

渗碳工艺下纯Ti板显微组织及晶粒长大动力学

研究不同渗碳工艺对纯Ti板微观组织和表面强化的影响,分析了晶粒长大阶段动力学特征。根据不同热处理温度(600、700、800℃)及时间(3、6、9h)下光学显微组织的转变规律,纯Ti板渗层硬度随渗碳温度升高和保温时间延长的变化趋势,确定500℃+1h真空预处理和700℃+6h渗碳处理为较佳渗碳工艺。分析了长大阶段晶粒平均尺寸变化,计算不同温度下晶界迁移速度,确定长大动力学时间指数和晶粒长大激活能分别为0.5、72.02kJ·mol-1,表明晶粒长大阶段激活能主要由空位激活能和晶界扩散激活能共同作用引起。     

固溶处理对GH4169合金组织与性能的影响

研究了热处理温度和保温时间对GH4169合金晶粒长大规律和硬度的影响.结果表明,δ相对晶粒长大有显著阻碍作用,在低于δ相完全溶解温度热处理时,未溶解的δ相使晶粒长大缓慢;在高于δ相完全溶解温度热处理时,合金为单相奥氏体组织,晶粒随温度的升高迅速长大.晶粒长大动力学表明:在热处理温度高于1050℃时的晶粒长大激活能为157.6kJ/mol,晶粒长大机理为Ni基合金的晶界扩散过程所控制,同时也建立了相应的晶粒长大动力学方程.     

FGH96合金晶粒长大规律的研究

对FGH96合金在热处理过程中晶粒长大规律进行了系统的研究。结果表明，γ’相对晶粒长大有显著阻碍作用，在低于γ’相固溶温度(1109℃)热处理时，大量未溶解的γ’相使得晶粒长大缓慢；在高于γ’相固溶温度以上时，合金为单相奥氏体组织，晶粒随温度的升高快速长大。晶粒长大动力学表明：在高于，相固溶温度以上时，晶粒生长指数随着热处理温度的升高而增加；在热处理温度为1135℃和1150℃下的晶粒长大激活能为293．4kJ／mol，晶粒长大机理为自扩散过程控制机理，并建立了相应的晶粒长大动力学方程。     

正挤压-扭转变形镁合金的组织热稳定性

将AZ31镁合金经过FETD工艺后在150~500℃之间进行退火处理,进行微观组织的热稳定性分析,研究晶粒在不同退火温度下的长大行为,计算出不同温度范围段的晶粒长大激活能。结果表明:平均晶粒尺寸随退火温度的增加而增加,晶粒尺寸最大达13.56μm;晶粒长大的激活能随着温度增加,在中温区间(300~400℃)反而减小,在高温区间(400~500℃)激活能达到最大值为86.07 k J/mol。     

固溶处理对GH4169合金组织与性能的影响

研究了热处理温度和保温时问对GH4169合金晶粒长大规律和硬度的影响。结果表明，δ相对晶粒长大有显著阻碍作用，在低于δ相完全溶解温度热处理时，未溶解的δ相使晶粒长大缓慢；在高于δ相完全溶解温度热处理时，合金为单相奥氏体组织，晶粒随温度的升高迅速长大。晶粒长大动力学表明：在热处理温度高于1050℃时的晶粒长大激活能为157．6kJ／mol，晶粒长大机理为Ni基合金的晶界扩散过程所控制同时也建立了相应的晶粒长大动力学方程。     

固溶处理对GH4169合金晶粒长大和硬度的影响

研究了GH4169合金在不同固溶温度和保温时间下进行固溶处理时晶粒长大的规律和其对硬度的影响。结果表明:该合金的δ相溶解温度在980～1000 ℃之间,不同固溶处理条件下GH4169合金的晶粒长大具有不同特点,在低于δ相溶解温度热处理时晶粒长大缓慢,当热处理温度高于δ相溶解温度时,晶粒尺寸随热处理温度的升高而快速长大;建立了GH4169合金在1000 ℃以上热处理过程中的晶粒长大动力学模型,晶粒长大的激活能为285.013 kJ/mol;GH4169合金的硬度随固溶温度的升高和保温时间的延长而降低,且合金的晶粒尺寸和硬度值遵循Hall-Petch关系。     

热处理对C-276合金无缝管晶粒长大行为的影响

研究了不同的热处理工艺对C-276合金冷轧无缝管晶粒长大行为的影响。结果表明:在同一保温时间下,随热处理温度的升高,C-276合金的晶粒尺寸逐渐增大,且不同保温时间下的晶粒长大趋势相同。当热处理温度为1040～1080 ℃时,晶粒长大较快;在1080～1160 ℃时放缓;在1160～1200 ℃时又加快。在1040～1200 ℃下保温10 min后C-276合金的晶界迁移表观激活能为313.77 kJ/mol。当热处理温度为1040～1080 ℃时,随保温时间的延长晶粒长大较为缓慢;温度为1120～1160 ℃时,当保温时间在10 min内,晶粒长大较快,当保温时间大于10 min后晶粒长大减慢;温度升高到1200 ℃时,随保温时间的延长晶粒长大趋势较为平缓。热处理温度在1040～1200 ℃范围内,随温度的升高,C-276合金的晶粒长大动力学时间指数η先增大后减小。     

铍晶粒长大规律研究

对铍在等温热处理过程中晶粒长大规律进行了系统的研究.结果表明,伴随铍晶粒长大,铍中杂质(BeO,Be2C)在晶界聚集,对晶粒长大有阻碍作用,促使晶粒长大趋势发生改变;铍晶粒长大动力学表明:晶粒生长指数随着热处理温度的升高而减小;在热处理温度为900、1050和1200 K下的晶粒长大激活能为40985J/mol,并建立了相应的晶粒长大动力学方程.     

纳米晶Co_(78)Ni_(22)合金热稳定性

采用DSC、XRD和TEM等手段研究了喷射电沉积制备的5.1 nm纳米晶Co78Ni22合金的热稳定性,并对其热力学参数进行了分析与计算。结果表明,该纳米Co-Ni合金具有良好的热稳定性,以10℃/min加热时的DSC放热峰值对应温度为389.9℃,放热焓为14.26 J·g-1,晶粒长大激活能为269.1 kJ·mol-1。在加热过程中,温度为340℃时,合金晶粒尺寸急剧长大,同时ε相向α相转变,相变的结束温度约为370℃,高温形成的α相在随后冷却中不发生转变。DSC测定的晶粒长大为相变结束后的α相晶粒长大,其激活能与自扩散激活能相近,因此晶粒长大由晶内扩散控制。     

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.