多自由度数字射线成像检测系统设计

针对目前运载火箭箱底、筒段、圆环零件的焊缝采用传统胶片照相进行检测，存在自动化程度低、过程繁琐、数字化程度低、且底片无法进行长期保存，无法满足当前多型号火箭并举下的快节奏研制需求.运用X射线与成像板相结合的无损检测方法，采用双七轴机器人和同步升降转台作为运动执行机构，采用ADS多线程通信与Ethercat总线方式实现倍福控制器、成像检测软件、射线机、机器人和同步升降转台的实时通信，研发了一种基于机器人的多自由度数字射线成像检测系统，通过运动执行机构的路径规划与无损检测焊缝成像实现产品环缝、纵缝、变曲率焊缝的检测自动化，与传统胶片照相相比，检测效率提升5倍，检测精度提高42%，满足了目前对多型号火箭贮箱的检测工作.     

火箭贮箱筒段搅拌摩擦焊缝圆度影响因素研究

2219铝合金被广泛应用于新一代运载火箭贮箱结构,搅拌摩擦焊接技术因焊接性能好等优点被广泛应用于贮箱焊接.然而贮箱完成焊接后,筒段搅拌摩擦焊缝处圆度时常不理想,绝热层因此发生局部开裂现象,不满足低温绝热要求,甚至导致火箭发射失利,因此开展新一代运载火箭贮箱筒段搅拌摩擦焊缝圆度分析与研究.通过开展贮箱焊接、充压等试验以分...     

2219铝合金双轴肩搅拌摩擦焊工艺及工程应用

针对5.4 mm厚度2219铝合金,开展了浮动式双轴肩搅拌摩擦焊接试验及工程化应用研究,采用低转速、高焊速的工艺参数,获得了成形美观、性能优良的焊接接头。焊缝超声相控阵检测及X射线检测均满足航天行业相关标准一级焊缝的要求,接头平均抗拉强度达到了母材性能的70%以上,断后伸长率达到6.5%以上。焊接接头均为45°剪切韧性断裂,塑性良好。整个焊缝截面呈上、下宽,中间窄的细腰形,焊缝两侧热力影响区为抛物线轮廓,未出现焊核凸出现象。在前期大量试验验证的基础上,率先实现了该技术在运载火箭贮箱焊接生产上的工程化应用,成功完成了某型号燃料贮箱筒段纵缝的焊接,焊缝顺利通过了常温液压及液氮低温试验考核。     

TIG弧焊机器人系统在宇航大型铝合金贮箱箱底拼焊中的应用

对TIG弧焊机器人应用于宇航大型铝合金贮箱底的拼焊技术进行了初步探讨，介绍了机器人系统的构成，研究了机器人的示教，再现过程，选定了焊拉工艺参数，认为弧焊机器人焊接宇航大型铝合金贮箱箱底有很好的应用价值与前景。     

超大直径贮箱箱底整体旋压成形技术

目前,国内大型贮箱箱底采用瓜瓣顶盖拼焊的方法制造,存在制造可靠性不足、生产效率低等问题。针对大型贮箱箱底制造现状,以某型号运载火箭贮箱箱底作为研究对象,设计了先预成形、后旋压成形的工艺方案,并提出了"一道次剪旋+多道次普旋"的旋压工艺方案,通过有限元仿真分析及工艺试验验证了超大直径贮箱箱底整体旋压成形技术的可行性。结果表明:采用预成形方案能够有效抑制零件边缘起皱,采用剪切旋压与普通旋压相结合的成形工艺能够实现箱底的高精度成形。箱底中心区域采用剪切旋压,构件形状可控性好,模具贴合良好;预成形法兰的边缘区域刚度高,采用多道次普通旋压,既能够达到收边贴模的目的,又能够避免边缘减薄量过大的问题。     

我国10m级高强铝合金重型运载火箭连接环样件实现一体化打印

国家增材制造创新中心、西安交通大学卢秉恒院士团队利用3D打印技术制成了10 m级高强铝合金重型运载火箭连接环样件。该样件利用电弧熔丝增减材一体化制造技术,在整体制造的工艺稳定性、精度控制及变形与应力调控等方面均实现重大技术突破。据了解,10m级超大型铝合金环件是连接重型运载火箭贮箱的筒段、前后底与火箭的箱间段之间的关键结构件。     

中国研制成功火箭燃料长筒段贮箱

正2021年2月下旬中国首个3.35 m直径火箭长筒段贮箱在中国航天科技集团八院800所问世,经过各项检测和强度考核,各项指标均超过预定值,完全具备工程应用条件。该贮箱筒段为5 m级长的,过去中国用的为小于2 m长的,而美国用的是4 m长的,采用长筒段,可以减少筒段壁板零件及环向焊缝数量,从而提高制度精度、承力性能及可靠性,标志着中国已掌握了长筒段制造技术,在火箭高质量、高效率、低成本研制上又取得了重大突破。     

推进剂贮箱薄壁箱底搅拌摩擦焊

针对新一代运载推进剂贮箱2 mm薄壁箱底高质量、高可靠、快速制造的研制需求,分析了产品焊接制造的特点及难点,结合搅拌摩擦焊技术自身特点,制定了焊接工艺方案,解决了关键技术,进行了产品试制.将搅拌摩擦焊技术应用于推进剂贮箱薄壁箱底焊接,进行了焊缝质量检验和液压强度试验,通过了性能考核.     

热处理对2A14铝合金组织和性能的影响

研究了不同热处理条件下2A14铝合金火箭贮箱主要结构的显微组织、硬度和力学性能。结果表明:2A14铝合金火箭贮箱基材的显微组织均为变形组织,焊缝区为枝晶组织,部分区域存在一定数量的气孔缺陷,热影响区是整个焊接接头最薄弱的位置;贮箱箱底与箱体母材硬度几乎相同,远高于叉形环母材硬度;箱底的力学性能最好,箱体次之,叉形环最差;固溶时效前的退火处理可以促进第二相溶入基体,使2A14铝合金获得优良的综合性能。     

大型超低温贮箱焊接质量检测试验技术

针对新一代运载火箭大型超低温贮箱结构和使用工况的特殊性,文中对贮箱焊接质量的检测试验技术进行了系统性论述,介绍了常温纯水液压试验、低温液氮液压试验及氦质谱泄漏检测等强度和密封试验技术在新一代运载火箭贮箱上的应用,并对其焊接质量控制要点进行了总结。     

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.