等离子旋转电极雾化工艺制备FGH96合金粉末颗粒的组织

采用扫描电镜(SEM)、透射电镜(TEM)等多种手段对等离子旋转电极雾化工艺(PREP)制备的不同粒度FGH96合金粉末显微组织进行研究,结果表明:200～300μm的粉末颗粒凝固组织呈现典型的树枝晶特征,-50μm的粉末颗粒凝固组织呈现典型的胞状晶特征;粉末在快速凝固过程中会析出不同形貌的亚稳碳化物MC’,不同形貌的MC’碳化物化学组成和点阵常数具有一定的差异。     

等离子旋转电极雾化FGH95高温合金粉末的预热处理

在不同热处理制度下对等离子旋转电极雾化(PREP)FGH95高温合金粉末颗粒进行预热处理，并对热处理粉末颗粒微观组织、碳化物析出相及γ相的变化规律进行研究。结果表明：随着预热处理温度升高，树枝晶组织逐渐消失，γ相由圆形逐渐转变为方形，粉末颗粒中的MC′型亚稳碳化物发生分解和转变，析出稳定的MC，M23C6及M6C型碳化物。M23C6碳化物的析出温度为950℃，M23C6与M6C碳化物的相互转变温度为1000～1050℃，M23C6和M6C的溶解温度为1100℃。     

预处理过程中FGH96合金粉末中的碳化物演变

采用扫描电镜、透射电镜等手段研究了预处理前后FGH96合金粉末颗粒中的碳化物演变。结果表明:粉末在快速凝固过程中会析出不同形貌的MC’型亚稳态碳化物,MC’碳化物中含有较多的弱碳化物形成元素,不同形貌的MC’型碳化物的化学组成与点阵常数具有一定的差异。在粉末预处理过程中,粉末颗粒内部形成的亚稳态MC’型碳化物逐渐转变为稳定MC型碳化物,同时可形成M23C6和M6C碳化物;转变后的MC型碳化物形态以规则块状为主,成分上以强碳化物形成元素Ti,Nb,Zr为主。     

镍基高温合金快速凝固粉末颗粒中MC型碳化物相的研究

对等离子旋转电极雾化（PREP）法制备的FGH95镍基高温合金粉末中碳化物的形态、结构、成分及其稳定性进行了实验研究,分析了粉末颗粒凝固过程中的热学参数和非平衡溶质分配对碳化物形成过程的影响．结果表明：快速凝固FGH95合金粉末中亚稳MC型碳化物形态的几何完整度随粉末颗粒尺寸减小由规则形态向复杂形态变化,不同尺寸粉末颗粒中碳化物的形态和数量决定于凝固过程中热学参数的变化和非平衡溶质分配系数的不同．亚稳MC型碳化物在加热作用下发生分解及合金元素再分配,其形态由复杂形状为主转变为规则形态的稳定MC型碳化物．     

快速凝固水雾化高速钢粉末的凝固特征

理论计算表明,水雾化M3/2高速钢粉末的平均冷却速率在105-107K/s之间.粉末颗粒的凝固组织主要以等轴晶为主,碳化物以空间网络状分布于等轴晶的晶界处.粉末基体组织以奥氏体为主,仅小粒径粉末基体由奥氏体与δ铁素体组成.碳化物主要为立方MC型和密排六方M2C型.     

激光沉积修复GH738合金时效热处理组织及性能

研究了双极时效热处理对激光沉积修复GH738合金显微组织及力学性能的影响。结果显示:沉积态显微组织为典型的外延柱状枝晶,枝晶间距约为10μm。经过时效处理后,修复区组织开始长大、合并。沉积态未发现γ′相,枝晶间存在立方状的MC型碳化物,枝晶干存在颗粒状M_23C_6型碳化物。经双级时效处理后,修复区析出γ′相:稳定化温度为820℃时,γ′相平均尺寸约为37 nm,碳化物在晶界处呈断续状析出。随着稳定化温度升高,γ′相及碳化物尺寸均有所增大,其中稳定化温度为840℃时,γ′相平均尺寸约为76 nm,碳化物呈项链状析出;稳定化温度为860℃时,γ′相平均尺寸无明显增大,部分γ′相发生明显粗化,尺寸达到150 nm,晶界处碳化物开始呈包膜状析出。力学性能测试结果显示:时效处理后试样抗拉强度明显提高,随着稳定化温度升高,抗拉强度先升高后降低,断后伸长率不断降低。     

激光沉积修复GH738合金时效热处理组织及性能研究

研究了双极时效热处理对激光沉积修复GH738合金显微组织及力学性能的影响。结果显示：沉积态显微组织为典型的外延柱状枝晶,枝晶间距为约10 μm。经过时效处理后,修复区组织开始长大、合并。沉积态未发现γ＇相,枝晶间存在立方状的MC型碳化物,枝晶干存在颗粒状M23C6型碳化物。经双级时效处理后,修复区析出γ＇相：稳定化温度为820℃时,γ＇相平均尺寸约为37nm,碳化物在晶界处呈断续状析出。随着稳定化温度升高,γ＇相及碳化物尺寸均有所增大,其中稳定化温度为840 ℃时,γ＇相平均尺寸约为76 nm,碳化物呈项链状析出;稳定化温度为860℃时,γ＇相平均尺寸无明显增大,部分γ＇相发生明显粗化,尺寸达到150 nm,晶界处碳化物开始呈包膜状析出。力学性能测试结果显示：时效处理后试样抗拉强度明显提高,随着稳定化温度升高,抗拉强度先升高后降低,断后伸长率不断降低。     

铪对粉末冶金高温合金FGH97粉末颗粒的影响

研究了不同Hf含量的FGH97合金松散粉末和断口中粉末的组织及析出相。结果表明,粉末颗粒内部的碳化物主要是富Nb、Ti、Hf的MC型碳化物,同时发现粉末颗粒内部存在Zr的氧化物。Hf能进入到粉末颗粒中MC碳化物内,并促进稳定MC碳化物的析出,适量的Hf有利于消除合金中原始粉末颗粒边界(PPB)。粉末颗粒表面的Hf以HfC和HfO2复合形式存在,Hf含量大于0.6%时会对PPB有不利影响。     

单晶高温合金激光表面快速凝固显微组织的TEM研究SCIEI

本文利用TEM及STEM-EDAX研究一种单晶高温合金的激光表面快速凝固显微组织。结果表明,快速凝固胞状树枝晶间存在着各种形态极为奇特的花状MC碳化物(TiC);而基体组织中有极其细小弥散的γ′沉淀相析出并存在较高密度的位错。     

镍基粉末高温合金原始颗粒边界形成及组织演化特征

采用等离子旋转电极(PREP)法制备高温合金粉末,通过热等静压(HIP)和热挤压(HE)进行固结成型,对制备的粉末及HIP、HE态合金内部和表面显微组织进行表征,探索镍基高温合金原始颗粒边界(PPB)的组成、形成机制及组织演化特征。结果表明:合金在粉末态已发生元素偏析,粉末表层有细小的富Al氧化物颗粒,且颗粒表面有Zr、C、O元素的富集层;合金PPB主要为连续的大尺寸??相、MC型碳化物、Al2O3和富Zr的氧化物颗粒;PPB形成机制是在温度场的作用下,碳化物、??相和氧化物易于在结合面析出,合金经热挤压后,原始颗粒边界上大的??相完全消失,连续的PPB被破碎,形成含MC碳化物和少量氧化物的沿挤压方向竖状排列的小颗粒,此时,合金已完成动态再结晶。     

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.     

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。     

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.     

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.