氩弧重熔工艺对GCr15钢硬度的影响

对GCr15轴承钢进行了不同工艺参数的氩弧重熔处理,利用维氏硬度计对其表面及横截面的硬度进行了测试和分析。结果表明,在一定工艺参数范围内,重熔电流大小对表面硬度值不呈单调变化,且重熔电流对淬硬层和过渡层深度随电流值增加而增加;重熔速度对表面硬度影响不大,但重熔淬硬层和过渡层的深度随重熔速度增加而降低;气流量过大,降低试样表面硬度,使淬硬层变浅,而对过渡层影响甚微。     

氩弧重熔对Q235钢热浸镀铝层组织和性能的影响

采用氩弧重熔技术对Q235钢热浸镀铝层进行改性处理,利用扫描电子显微镜和X射线衍射仪对重熔前后组织进行了观察,并测定了重熔前后截面显微硬度.研究了重熔工艺参数对热浸镀铝层组织和性能的影响.结果表明,热浸镀铝层经氩弧重熔处理后,分层现象消失,组织上梯度过渡,试件由重熔层和淬硬层及基体构成.氩弧重熔处理能明显提高热浸镀铝层的显微硬度.氩弧重熔工艺参数对重熔层深度、硬度和裂纹率影响较大,焊接电流增加或焊接速度减小时,重熔层深度增加,硬度升高,裂纹率下降.     

等离子束表面处理对硼铸铁组织与性能的影响

研究了等离子束表面硬化工艺参数对硼铸铁淬硬层及其组织与性能的影响.实验结果表明:硼铸铁经等离子束淬火处理后,其硬化层的组织为隐针马氏体 残余奥氏体 片状石墨 硼化物,其显微硬度是未处理的2～3倍,且硬度分布沿硬化层深度方向很不均匀.在扫描速度不变的条件下,随电流增大,硬化层深度和宽度增加,显微硬度增大;在电流不变的条件下,随扫描速度增大,硬化层深度和宽度减小,显微硬度减小.     

氩弧硬化对硼铸铁表面组织和性能的影响

采用氩弧重熔技术在硼铸铁表面进行表面硬化改性处理,研究了钨极氩弧硬化工艺参数对硼铸铁表面组织和性能的影响.结果表明,硼铸铁表面采用氩弧热源淬火时,淬硬层与基体之间过渡区明显,硬化区组织为莱氏体,过渡区组织为马氏体 残留奥氏体 少量石墨.氩弧硬化工艺参数对硬化层的深度、硬度和裂纹率影响较大,工作电流增加或扫描速度减小时,硼铸铁表面硬化层深度增加,硬度降低,裂纹率下降.在保证不出现裂纹的条件下,硬化层表面的硬度值最高可达64 HRC,硬化层显微硬度值最高可达1196 HV0.1,其耐磨性明显高于未经处理和经激光表面处理的硼铸铁.     

扫描速度对共析钢等离子表面淬火硬化的影响

以层流等离子弧作为热源对共析钢进行表面淬火,通过等离子表面淬火热传导的理论分析,对等离子弧扫描速度对硬化层最大硬化深度的影响进行研究。并利用电子扫描显微镜、显微硬度计等试验手段,研究了淬火硬化层的显微组织和力学性能。结果表明:层流等离子弧扫描速度越快,淬火硬化层最大硬化深度越小。得出等离子弧扫描速度与淬火硬化层最大硬化深度之间的关系,并且与实验结果相吻合。淬火硬化层组织为板条状马氏体和针状马氏体,淬火硬化层与基体的界面组织为珠光体和隐针马氏体,基体组织为珠光体。淬火硬化层硬度由共析钢基体的350 HV提高到900～1000 HV。     

Cr12MoV钢的高功率半导体激光表面硬化

应用高功率半导体激光器对Cr12MoV钢表面进行硬化处理。研究了扫描速度、加热温度以及搭接率等工艺参数对Cr12MoV钢表面硬度以及淬硬层深度的影响。试验结果表明,当扫描速度固定时,随着加热温度的升高,表面硬度和淬硬层深度增加;当加热温度固定时,随着扫描速度的升高,表面硬度和淬硬层深度下降;搭接率为30%时,表面硬度的波动幅度最小。     

45钢等离子弧表面淬火技术的研究与应用

以45钢为典型材料，进行了等离子弧表面淬火技术工艺试验研究。分析了加热功率、扫描速度、喷嘴直径以及弧柱长度等因素对淬火硬度、淬火深度、相变区域的金相组织诸方面的影响规律，同时，对不同冷却方法的淬火效果进行了试验研究，从而确定了45钢等离子弧表面淬火的工艺方法。     

激光淬火工艺参数对HT210淬硬层深及硬度的影响

利用正交试验法分析了多道次激光淬火试验,研究了激光淬火工艺参数对灰铸铁淬硬层深及表面硬度的影响。试验结果表明,搭接宽度影响的是淬硬层的平均层深和硬度,对最大层深和最大硬度没有明显的影响;扫描速度增大,淬硬层深和硬度都会降低,当激光功率过大时,试样表面淬火区会熔化、出现裂纹,硬度会比未完全熔化的试样高;激光功率增大,淬硬层深和硬度都会升高,扫描速度较低时,激光功率的变化对淬硬层深及硬度的影响更为明显。     

42CrMo钢折弯模具激光表面强化

利用扫描电镜、电子背散射衍射技术等手段研究了42CrMo钢折弯模具的激光表面淬火特性。研究结果表明,激光扫描速度、功率、工件厚度等对淬硬层深度及硬度有显著影响。在激光功率2200 W、扫描速度1800 mm/min、光斑ϕ2 mm、辅助水冷、一道次扫描条件下,折弯模具刀刃硬度和淬硬层厚度分别达到734 HV0.2和1.05 mm,且刀刃两侧的硬度分布均匀。激光淬硬层组织为细小的马氏体,尤其靠近基体处。     

柴油机气缸套表面等离子束改性工艺

针对柴油机气缸套磨损失效现象,采用高能等离子束在常压下快速扫描气缸套内表面,对其进行局部硬化改性处理,获得了高硬度淬火硬化层.不同参数工艺试验结果表明,工作电流越大、扫描速度越低,硬化区表层残留奥氏体含量越少;扫描速度不变,工作电流越大,硬化层深度越深、硬度越高;工作电流不变,扫描速度越低,硬化层深度越深、硬度越高.     

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.