铝型材粉末静电喷涂生产工艺条件优化

介绍粉末涂料静电喷涂的工艺原理及工艺流程,从粉末涂料质量和喷涂工艺控制两方面分析影响粉末喷涂产品质量的主要影响因素.对静电喷涂电压、供粉气压、固化温度及时间等喷涂主要参数设计了4因素3水平的正交试验,研究喷涂工艺参数对产品机械性能的影响,结果表明:影响涂层机械性能的因素主次顺序是固化温度、供粉气压、固化时间、静电电压,铝型材静电喷涂的较佳工艺参数为:粉末粒径20～80μm ,喷涂环境湿度＜85%,静电喷涂电压40～60kV,压缩空气0.5MPa,固化温度190℃,固化时间20min.这些喷涂条件对提高喷涂产品质量和优等率具有很高实用价值.     

铝型材静电粉末喷涂生产控制及常见缺陷分析

介绍了静电粉末喷涂原理。对喷粉工艺及控制、固化条件、涂层质量要求和常见缺陷进行了分析，提出了对策。     

静电喷涂在农机行业的应用

介绍了静电喷涂的特点及其在农机行业履带拖拉机后桥变速箱合件的应用情况。并就如何选择设备以及选用的效果进行了阐述。     

钢管粉末静电喷涂工艺

详细介绍了钢管粉末静电涂装生产工艺和原理以及对钢管表面进行化学、机械的预处理工艺。     

铝型材挤压模的修模技术

介绍了铝型材挤压模修正的基本原则和修模的基本方法。并针对实心型材挤压和空心型材挤压时，挤压制品出现的缺陷形式，分析了产生的原因，给出了相应的修模方法。     

KBE技术在铝型材挤压模具设计中的应用

将KBE技术应用于铝型材挤压模具设计中，通过充分利用多来源的领域知识对铝型材模具设计提供最大限度支持，提高工程决策有效性。本文介绍了铝型材挤压模具KBE原型系统框架及其关键技术。     

铝型材挤压模具的精密研磨技术

本文通过理论分析和实验结果，证明了对经电加工后后铝型材挤压模具工作带进行挤压珩磨抛光和超声波清洗是理想的精密研磨技术，有效地支队了变质层的残余应力，表面粗糙度小于Ｒａ＝０．４μｍ，满足了该模具ＰＣＶＳＴｉＮ的工艺要求。     

The oxidation behavior of gas-atomized Al and Al alloy powder green compacts during heating before hot extrusion and the suggested heating process

The oxidation behavior of gas-atomized Al and Al alloy powder green compacts during heating prior to hot extrusion compaction was studied at laboratory and industrial scales by TGA, DSC, DTA, EDX, TEM and XRD methods. The effect of the heating of green compacts on the mechanical properties of the powder-extruded samples was assessed. Significant oxidation of Al and Al alloy powder green compacts takes place in the solid state during heating in air. The onset and intensity of oxidation were affected by the Mg content, the surface area of the powder and the volume of the powder green compacts. An exothermic heat associated with the oxidation of Al and Al alloy powders resulted in intense overheating of bulky powder green compacts during heating in air. The samples extruded from the powder green compacts heated in air exhibited reduced strength. The loss in strength was especially pronounced in the case of Mg-containing Al alloy powders. Mg diffuses from a powder metallic core toward the native Al₂O₃ surface layer present on as-atomized Al alloy powders; it reacts with oxygen present in air and in the Al₂O₃ surface layer where the MgO phase forms, eventually resulting in the depletion of Mg from the powder core. Materials extruded from Al powders depleted of Mg do not exhibit effective Al-Mg solid solution strengthening or strengthening by Mg-containing precipitates. Economically viable approaches to avoiding the detrimental effects of powder oxidation during the heating of green compacts prior to hot working consolidation are discussed.     

SiC_p/2024铝合金复合材料粉末混合半固态挤压法制备

研究了SiCp/ 2 0 2 4铝合金复合材料的粉末混合 半固态挤压成形工艺及所制备材料的组织和界面特征。不同温度下半固态挤压的挤压力与位移曲线表明 ,半固态挤压过程的成形力低且稳定。SEM和TEM电镜观察结果表明 ,该工艺可以获得增强颗粒分布均匀、基体组织致密、界面结合良好且无界面反应的复合材料型材。分析了半固态挤压后复合材料的力学性能 ,结果表明 :与基体合金相比 ,复合材料的弹性模量、屈服强度、抗拉强度均有很大提高 ;与其它工艺生产的该复合材料相比 ,所制备的复合材料的塑性相对较高。     

金属铝粉表面纳米膜包覆

采用扫描电镜、透射电镜和X射线光电子能谱仪对包覆有纳米膜的复合金属铝粉进行分析,发现纳米包覆膜的厚度为10 nm左右;金属粉的比表面积(BET)由包覆前的1.46 m2/g,包覆后增加到13.74 m2/g,提高了粉体的分散性;包覆后的铝粉孔径-孔容图呈很好的光滑曲线,表现出良好分散颗粒的孔径-孔容分布特征.热分析研究表明,包覆后的铝粉热量释放更大、更快速、更集中,适合于固体推进剂所要求的能量释放特点.     

挤压速度对双坯料连续挤压6063铝合金焊合性能的影响

在双坯料连续挤压过程中,由于两根坯料汇合而形成挤压焊缝.通过显微组织观察、拉伸试验、扫描电镜研究挤压轮转速对6063铝合金焊缝显微组织形貌和性能的影响,并通过有限元仿真分析焊合参数.结果表明,在连续挤压过程中,坯料外表面的氧化物对金属焊合有显著影响,随着挤压速度的增加,等效应变速率明显增加,造成焊合面上的氧化物的破碎程...     

Rheological properties of feedstocks for powder extrusion molding

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纯铝粉末多孔烧结材料等通道转角挤压致密化行为研究

对纯铝粉末烧结材料进行等通道转角挤压实验,结果表明:经一次挤压后主要变形区组织剪切变形特征明显,内部的孔隙基本闭合,组织明显细化;多道次挤压后,不同挤压路径得到材料组织形态及孔隙闭合效果不同.研究认为,单道次ECAE过程中的孔隙闭合效果取决于试样所处的应力状态,即剪应力和球应力张馈的良好匹配是材料获得良好的致密效果的关键.多道次挤压由于变形量的累积和不同的剪切特征不断改变基体及孔隙的形状,使材料进一步致密.     

Controlling Al/Cu composite diffusion layer during hydrostatic extrusion by using colloidal Ag

In this study, intermetallic compound formation at the interface between aluminum and copper during hydrostatic extrusion was simulated by performing a solid state diffusion bonding experiment with various processing parameters, including bonding temperature and pressure and holding time, and by inserting an Ag colloid layer between the aluminum and copper. Regression equations were developed to predict thickness of diffusion layer and interface hardness.An intermetallic compound formed at the interface between the Al and Cu during diffusion bonding at 420 °C and 240 MPa for 60 min, and it was effectively controlled by inserting an Ag colloid. These experimental data will be useful for setting up processing parameters to prepare Al/Cu matrix composite materials by using hydrostatic extrusion.     

Fabrication and properties of binder for powder extrusion molding

By optimizing formulation and fabrication methods, a new binder for plasticizing powder extrusion molding of hard metal, with excellent integrated properties and uniform distribution characters, has been developed. Thermal debond-ing mechanism and the extruding rheological behaviours have been studied. The technology of fabrication of binder and thermal debonding process have also been investigated. Using the novel binder, the hard-metal extrusion-molding rods with diameter up to 25mm, have been manufactured.     

Ge–Al and Sn–Al alloys capillary properties in contact with aluminum nitride

Experimental isotherms are presented for (1) wettability of AlN ceramics by Ge–Al and Sn–Al alloys, (2) surface tension and density of Ge–Al and Sn–Al alloys in the whole concentration range. Complex consideration of capillary characteristics of the melts under study is performed taking into account data available on thermodynamic activities of the melt components. The contact angle isotherms pass the minimum point for both systems. The contact angle value drops with Al addition more sharply for the Sn–Al system than for the Ge–Al alloys. This is in qualitative agreement with the higher thermodynamic activity of the components of the Sn–Al alloys. Sn decreases Al surface tension more than Ge. The reason for this is not only lower surface tension of Sn as compared to Ge, but also the higher thermodynamic activity of Sn in the Al melt.