5A06铝合金复杂构件的复合挤压成形工艺

为了揭示5A06铝合金进行复合挤压成形复杂构件时的金属流动成形规律以及力学性能的变化,根据复杂构件的形状结构特点,制定了复杂构件复合挤压成形工艺方案,并增加预成形阶段,使棒料被挤压成与挤压件外轮廓基本相同。研究了5A06铝合金在复杂应力状态下的变形行为,并利用Deform-3D软件模拟复杂构件的成形过程,研究了模拟结果的行程-载荷曲线、等效应力以及金属流线分布,最终利用THP61-3 MN数控液压机进行产品试制。研究结果表明,生产试制结果与模拟结果基本吻合,且复杂构件的性能得到了明显改善,模拟分析结果为成形工艺的完善与优化提供了理论依据。     

多道次加载下TC6钛合金作动筒等温锻造成形规律

对TC6钛合金作动筒锻件进行单/双/三道次加载成形路径分析,以单道次加载成形中的载荷剧增处为转变点,并在该处改变凸模加载速度,采用双道次和三道次对作动筒进行加载成形规律研究。通过平均成形载荷与成形时间之比来表征成形效率,并对比得出较好的加载成形路径,研究该加载路径下的成形载荷大小与材料流动规律,结果表明：通过对比成形效率得出平均载荷较小、成形效率较高的3种多道次加载路径。从材料流动角度分析了单道次压下量为13%时载荷剧增是由于凸模顶端的水平面与工件开始接触,材料流动变慢导致的;而在压下量为72%时载荷增加是因为工件已经和凹模底部开始接触,大量材料继续向侧向实心凸起处流动,少量材料向上反挤成形作动筒的上端。最后,通过实验与模拟验证表明,作动筒锻件在双道次加载路径下的筒体成形良好,底部实心凸起处充填饱满。多道次加载能够发挥钛合金的超塑性能,提高成形效率,精确塑性成形。     

加载条件对铝板电磁局部成形的影响

基于电磁成形冲击载荷大、成形效率高的特点,提出了将电磁成形局部加载方式应用于整体壁板的新思路。以2024铝板为研究对象,通过工艺实验和有限元模拟分析,研究了加载路径和加载间距对成形效果的影响。结果表明,加载路径和加载间距对板料变形程度的影响较大,从中间向两边的加载路径可得到最大的弯曲挠度为3.204mm,是从左到右加载路经的1.3倍;随着加载间距的增大,板料的塑性流动更为充分,弯曲挠度明显提高,有限元模拟结果与实验结果一致。     

筋板类锻件等温精密成形技术研究

主要研究筋板类锻件等温精密成形技术.针对典型筋板类锻件,设计了不同形式的局部加载垫板进行局部加载,通过局部加载技术控制腹板处多余金属的流动方向和距离,避免产生折迭、充不满等缺陷,并且利用等温变形条件改善金属充填质量和降低模压力.实验结果表明局部加载等温成形技术可以有效地控制金属的变形流动,提高筋板类锻件的成形质量.     

带侧枝复杂铝合金构件包络成形工艺分析与金属流线模拟

针对带侧枝复杂铝合金构件的几何特点,提出采用包络成形工艺成形该零件,并利用DEFORM-3D软件模拟了其成形过程,分析了等效应变和成形载荷变化特点,并通过DEFORM-3D软件的Flownet功能模拟了该构件包络成形过程中金属流线分布和演变特点,最后通过工艺实验进行了验证.结果表明:带侧枝复杂铝合金构件包络成形过程中,...     

管材内高压成形新加载方式的研究

介绍了管材内高压成形过程中,一种新的内压加载方式--脉冲型加载方式.并通过建立相应的有限元模型,进行了内压脉冲型加载方式下管材内高压成形过程的模拟.通过对不同加载方式模拟结果的比较,分析了脉冲型加载方式对内高压成形中金属流动、变形区变形分布及局部过度减薄等方面产生的影响.模拟结果表明:脉冲型加载在管材内高压成形过程中可以使变形区的变形更加均匀,有利于抑制局部过度减薄、对抑制最后贴膜成形的圆角部位的过度减薄作用明显;脉冲型加载方式使变形更均匀的原因是减小了金属流动阻力,使金属流动更容易.     

高强铝合金复杂筋板构件分流开放加载

针对7075高强铝合金复杂筋板构件成形过程中易产生折叠、充不满及载荷过大等问题,在分析其缺陷产生机理的基础上,提出针对此类复杂筋板构件的分流开放加载成形技术,通过控制分流开放加载高度Hy,使分流开放加载与材料成形之间过渡均匀,可有效降低构件成形载荷并避免因分流开放加载而产生的成形缺陷。在12.5MN数控液压成形设备上进行实验,成功试制出无缺陷的合格零件,成形载荷降低约60%,材料利用率提高了50%以上,且锻件的力学性能满足产品的服役条件。     

钛合金整体隔框等温成形局部加载分区研究

钛合金大型整体隔框在航空航天领域得到了越来越广泛的应用,等温局部加载为这类构件的成形提供了新的途径。等温局部加载过程复杂并且存在着加载区、未加载区和过渡区以及不同加载区之间的转换,合理的局部加载分区,是保证成形过程实施和成形质量的关键,文章研究并提出了局部加载分区的总体原则,随后基于DE-FORM3D有限元软件,采用数值模拟方法研究了局部加载分区(大小、位置)对TA15钛合金整体隔框成形过程的影响规律。结果表明,局部加载分区对未加载区材料错移的影响是短程效应,合理的分区可有效控制未加载区材料错移和降低总体成形载荷;分区对材料总体变形量和变形均匀性影响不大;采用筋上分区有利于提高筋的充填性能并可避免毛刺的产生,从而可提高了过渡区成形质量。     

涡旋盘精密模锻成形

以涡旋盘动盘为研究对象,基于流动控制成形技术提出在凹模中分别添加背压阻尼和分流腔的两种成形工艺方案,通过DEFORM-3D软件对两种成形工艺方案进行数值模拟和试验验证.模拟结果表明:采用背压结构,涡旋盘金属的流动性更好,但所需成形载荷较大,且凹模的等效应力和变形量较大;采用分流腔结构,所需成形载荷更小,凹模的等效应力和...     

镁合金复杂结构件超塑性成形模具型腔优化设计与数值模拟

依据零件几何特征和使用性能要求,设计了镁合金超塑性成形两种模具。利用Deform-3D软件对两种成形模具在不同温度和加载速率下即温度分别为350、375、400℃和加载速率分别为10、8、6、4、2、1mm/min时进行了超塑性成形的数值模拟,揭示了温度和加载速率对所需载荷的影响规律,获得了较佳的工艺参数,获得了优化工艺参数下的速度场、等效应力场、塑性流动方向以及载荷与行程的关系,分析了成形过程中应力和载荷变化的原因。     

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.     

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。     

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.     

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.     

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.