共查询到20条相似文献,搜索用时 15 毫秒
1.
介绍了一种自行发明的新的雾化方法。该方法是采用含有固体介质的高速气流即气固两相流对液体金属或合金进行雾化而制备粉末的一种方法,对比研究了同等条件下普通气体雾化与两相流雾化制备粉末的特征,研究了固体雾化过程中主要工艺参数对固体雾化粉末特征的影响规律。结果表明,两相流雾化制得粉末的平均粒度约为普通气体雾化所得粉末的二分之一,而且粒度分布更集中,粉末的冷却速度比普通气体雾化高一个数量级,粉末微观组织更细小;采用液体雾化破碎准则韦伯数以衡量雾化介质的破碎能力,得出两相流雾化介质的韦伯数为气体韦伯数和颗粒流韦伯数之和,建立了两相流雾化破碎的临界方程,并以此讨论了主要工艺规律。 相似文献
2.
3.
采用图像分析技术对4种不同方法制备的球形Ti-6Al-4V粉末进行粒形的定量分析,分别测量了粉末的球形度、椭圆率、赘生物指数及粗糙度。结果表明:4种方法制备的粉末平均球形度均在90%以上。等离子旋转电极雾化法(PREP)、等离子火炬雾化法(PA)、等离子惰性气体雾化法(PIGA)、电极感应熔炼气雾化法(EIGA)制得粉末球形度依次降低,粗糙度依次增加。PREP、PA、EIGA、PIGA法制得粉末的表面卫星球粘附依次增加。对于PREP法制得粉末,粉末粒径范围越细,球形度越高,平均粗糙度越小。粉末粒形指标的差异与其制备方法的原理有关。采用图像分析技术可以实现对金属粉末粒形指标的科学定量分析。 相似文献
4.
基于Laval喷嘴的层流气雾化技术可以高效制备高性能金属粉末,但目前对这种技术的各项工艺参数及粉末性能尚未有系统性研究。本工作使用基于Laval喷嘴的层流气雾化制粉设备制备了AlSi10Mg合金粉末,同时使用传统分析方法和X射线计算机断层扫描技术分别研究了雾化气体压力以及导流管内径对粉末整体形貌、三维形貌、球形度、粒度分布、物理性能及内部缺陷的影响,并结合数值模拟进行机理性解释。结果表明,基于Laval喷嘴的层流气雾化技术制备的AlSi10Mg粉末性能较好,由于在较高的雾化气体压力和较窄的导流管内径条件下气液流量比更高,金属熔体更易发生破碎,故制备的粉末球形度更好,粒度分布较窄,细粉收得率可接近50%,不规则粉末及空心粉较少。 相似文献
5.
固气两相流雾化工艺规律 总被引:4,自引:1,他引:4
采用高压氮气为气相雾化介质,分别以NaCl颗粒和Fe粉为固相雾化介质,对Al-Si合金、金属Zn进行固气两相流雾化实验,系统研究了工艺参数对粉末平均粒度和形貌的影响规律.结果表明,固气两相流雾化存在最佳的固/气流率比,采用的固体介质颗粒只有既达到较高的浓度又具有较高速度,才能极大地提高雾化效果.同时,较高密度的固体介质、低金属液流量有利于获得平均粒度细小、形貌复杂、粒度分布更集中的金属粉末. 相似文献
6.
M.Hohmann S.Pleier 《金属学报(英文版)》2005,18(1):15-23
Metal powders of superlative quality, i.e. high cleanliness, rapidly solidified and spherical shape, have seen an increasing demand in the market. The leading technology for the production of such powders is the inert gas atomization of metal alloy melts. To fulfill these requirements, the metal alloy is usually produced in a vacuum induction melting furnace (VIGA = vacuum induction melting/gas atomization) and poured by means of a preheated tundish system into a gas nozzle where the metal stream is disintegrated by a high kinetic energy inert gas jet. The produced micro-droplets solidify in a free fall inside the atomization tower. For special applications, super-clean and ceramic-free metal powders can be produced by using the EIGA (electrode induction melting/gas atomization) melting- and atomizing system.As an alternative to the metal powder route, the sprayforming technology allows to produce semi-finished products in one step. In this case, the metal droplets produced by the highenergy inert gas nozzle system are directly solidified on a substrate, allowing to form billets,rolls and tubes. 相似文献
7.
8.
9.
MICROSTRUCTUREANDMECHANICALPROPERTIESOFRAPIDLYSOLIDIFIEDAl-FeBASEDALLOYSW.J.Park;S.Ahn;R.Schmees;andNackJ.Kim(1)(CenterforAdv... 相似文献
10.
11.
采用高压气体雾化技术制备了Cu—Fe合金粉末,并对粉末的组织进行了观察分析.结果表明,雾化液滴的尺寸与合金成分影响凝固组织的演变过程.雾化液滴尺寸越小,其内部富Fe相越弥散;Fe含量越接近亚稳液态组元不混溶区域的临界成分,越容易发生液-液相变.分析表明,富Fe液滴的Marangoni迁移和富Fe粒子与固-液界面之间的相互作用是导致粉末外部形成贫Fe层的主要原因. 相似文献
12.
ZHANG Dengxia MA Chenghui CAI Ming Institute of Mechanics Academia Sinica Beijing ChinaAI Baoren ZHANC Jinyuan ZHU Ruizhen LIU Chunlan Central Iron Steel Research Institute Ministry of Metallurgical Industry Beijing China Associate Professor Institute of Mechanics Academia Sinica Beijing China 《金属学报(英文版)》1993,6(7):25-28
Observations of microstructure of explosive compacts made of Al or Al-Li alloy powdersby atomization with water,nitrogen or ultrasoic Ar gas were carried out under optical andscanning electron microscopes.The rsults indicate that super quality explosive compactcan only be obtained by powders of which the thickness of the oxide layer is less than30 nm. 相似文献
13.
14.
Effects of combinatorial water atomization on microstructures and properties of Cu-Sn powder 总被引:1,自引:0,他引:1
JIAChengchang MAHongqiu JINChenghai GELiqiang 《稀有金属(英文版)》2004,23(2):143-146
A couple of additional cooling nozzles were assembled under traditional atomization nozzles in order to improve the process and produce the powder with fine microstructure and low oxygen. The influence of the process parameters on the properties of the powder was investigated. The results show that fmer powders with lower oxygen content and more irregular shape can be achieved by combinatorial atomizing process comparing with normal one under the same atomizing pressure. 相似文献
15.
Al-20Sn-1 Cu powders were prepared by gas atomization in an argon atmosphere with atomizing pressures of 1.1 and 1.6 MPa.The characteristics of the powders are determined by means of dry sieving,scanning electron microscopy (SEM),optical microscopy (OM),and X-ray diffractometry (XRD).The results show that the powders exhibit a bimodal size distribution and a higher gas pressure results in a broad size distribution.All particles in both cases are spherical or nearly spherical and satellites form on the surface of coarse particles.Dendritic and cellular structures coexist in the particle.With decreasing particle diameter,the secondary dendrite arm spacing (SDAS) decreases and the cooling rate increases.The particles processed under high gas atomization pressure (1.6 MPa) exhibit a lower SDAS value and a higher cooling rate than those of the same size under low gas atomization pressure (1.1 MPa).The XRD results show that the Sn content increases with decreasing particle size. 相似文献
16.
利用真空感应熔炼气雾化法制备1720 MPa级马氏体时效钢粉末,研究雾化压力、过热度、气体加热温度对粉末特性的影响。结果表明,当雾化压力较高、过热度较高、气体加热温度较高的情况下,金属粉末的细粉收得率较大,松装密度较高,流动性较好。最佳雾化参数为漏嘴孔径ϕ5 mm、雾化压力5.0 MPa、过热度245 K、雾化气体温度100 ℃。该工艺条件下的时效钢粉末球形度良好,粉末流动性为20.15 s/50 g,松装密度为4.23 g/cm。 相似文献
17.
18.
采用真空感应熔炼气雾化法(VIGA)制备了M2052锰铜合金粉末,分析了M2052锰铜粉末的物性和显微组织;用选区激光熔化3D打印技术(SLM)制备锰铜试样,并分析热处理前后SLM成型的锰铜合金的组织与性能。结果表明,VIGA法能够有效地控制金属粉末形状,制备的15~53 μm粒度区间的锰铜粉末收得率高,松装密度高,具有较好的球形度,有效满足SLM用金属粉末的要求。由SLM制备的锰铜打印件横纵向具有不同的微观组织,随熔池内部延伸逐渐变为胞状晶,沿焊接界面形成柱状晶,离熔池越远柱状晶越细。与铸态合金相比,SLM方法制备的锰铜合金具有明显的力学性能差异,SLM打印件的抗拉强度为611 MPa,规定塑性延伸强度为504 MPa,远远高于铸态母合金的454 MPa和172 MPa。其原因是打印件细晶强化效果明显,但微裂纹的存在对塑性不利。 相似文献
19.
锌合金粉在KOH溶液中析氢行为的研究 总被引:1,自引:0,他引:1
采用气雾法制备Zn-In,Zn-Pb,Zn-Bi,Zn-Al合金粉,利用收集气体的办法测定了各种合金粉在KOH溶液中的腐蚀速度,确定了In,Pb,Bi,Al四种元素与Zn分别形成合金的最佳含量,随后研究了In,Bi,Al三种金属元素与Zn形成的四元合金的析氢行为。 相似文献
20.
In close-coupled gas atomization(CCGA), the influences of melt superheat on breakup process are fundamental to obtain desired or finer powder. Based on a series of Cu atomization experiment under different superheating conditions, the influences of melt superheat on breakup process were studied. Experimental results indicate that as the melt superheat is increased to 150, 200, 250 and 300 K, the mean particle size (D50) decreases consequently to 34.9, 32.3, 30.9 and 19.7 μm. Theoretical analysis reveals that the primary breakup and secondary breakup processes are close coupled, and the melt superheat radically influences the melt properties, and plays a crucial role on governing the filming process of primary breakup and the atomization modes of secondary breakup. There exists a strong nonlinear decrease of contact angle of melt to nozzle orifice wall when the superheat is increased fi'om 250 K to 300 K, leading to a marked fall of the film thickness formed in primary breakup, and D50 of copper powders is therefore sharply reduced. However, the log-normal distribution feature of particle size has not been substantially improved. 相似文献