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多组分铜基金属粉末选择性激光烧结成形的工艺研究 总被引:1,自引:0,他引:1
对多组分铜基金属粉末(组分包括纯Cu,预合金CuSn和CuP)进行了选择性激光烧结试验,其成形机制为粉末部分熔化状态下的液相烧结机制.研究了激光功率、光斑直径、扫描速率、扫描间距、铺粉厚度等工艺参数对粉末激光烧结致密化的影响.为便于整体调控激光烧结过程,本文将各工艺参数综合为"能量体密度"这一个参数,结果表明,增加激光功率或减小扫描速率能增加液相生成量,且利于液相的铺展和流动,进而提高润湿性和烧结性;扫描速率越高,则越易引起"球化"现象.减小铺粉厚度有利于获得较好的层间结合,并提高烧结致密度;若铺粉厚度过小,会降低铺粉均匀性,进而有损层间结合性.减小扫描间距使烧结线从断续分布转变为较为平整的结合状态,进而提高烧结致密度.当能量体密度增至一临界值(约0.15 kJ/mm3)时,烧结致密度有显著提高;但若增至过高(大于0.30 kJ/mm3),烧结致密度则呈下降趋势. 相似文献
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描述了激光选择性烧结金属粉末快速成形设备的粉末供给和铺平压实系统及动作,探讨了烧结过程参数对烧结质量的影响,粘结剂含量、孔隙率和缺陷尺寸与烧结件压缩强度之间的关系,并指出影响激光选择性烧结的重要因素是烧结粉末的特性、激光参数的设置等。 相似文献
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激光烧结金属陶瓷成形探讨 总被引:1,自引:0,他引:1
利用激光直接成形出高质量的金属、陶瓷及金属陶瓷复合材料零件是激光选择性烧结的最终目标。本文对激光烧结成形金属以及陶瓷材料进行了探讨与分析,对其中出现的问题作了初步的分析。 相似文献
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Microstructural evolution during direct laser sintering of multi-component Cu-based metal powder 总被引:1,自引:0,他引:1
A multi-component Cu-based metal powder was chosen for direct laser sintering. The powder consists of a mixture of high-purity Cu powder, pre-alloyed CuSn and CuP powder. Liquid phase sintering with complete melting of the binder (CuSn) but non-melting of the cores of structural metal (Cu) proves to be a feasible mechanism for laser sintering of this powder system. The microstructural evolution of the sintered powder with variation of laser processing parameters was presented. High sintering activities and sound densification response were obtained by optimizing the laser powers and scan speeds. Using a high laser power accompanied by a high scan speed gives rise to baUing effect. At a high laser power with a slow scan speed the sintering mechanism may change into complete melting/solidification, which decreases the obtainable sintered density. The role of additive phosphorus in the laser sintering process is addressed. Phosphorus can act as a fluxing agent and has a preferential reaction with oxygen to form phosphatic slag, protecting the Cu particles from oxidation. The phosphatic slag shows a concentration along grain boundaries due to its light mass as well as the short thermal cycle of SLS. 相似文献
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对不同CuP含量的多组分铜基金属粉末(Cu-CuSn-CuP)进行了选区激光烧结实验。利用X射线衍射和扫描电镜研究了添加元素P对烧结致密度及显微组织的影响。研究表明:P元素能在烧结过程中充当脱氧剂而与Cu反应生成CuPO3;但当P过量时,则会因熔体过热倾向明显而加剧氧化;适量增加P元素能改善烧结件层间结合性;而P元素过量则会因生成过多磷渣而降低润湿性及致密度;P元素亦能充当稀释剂而降低熔体粘度及表面张力,从而改善烧结致密度及组织均匀性;但若P元素过量时,则会因熔体粘度过低而导致球化现象。实验结果证实,该组铜基金属粉末体系中CuP的最佳含量为15%。 相似文献
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多组分铜基金属粉末选区激光烧结致密化机理 总被引:15,自引:2,他引:15
研究了选区激光烧结专用多组分铜基金属粉末(组分包括纯Cu,预合金CuSn,CuP)的烧结性能.结果表明,通过合理控制激光工艺参数(特别是激光功率和扫描速率),能顺利实现粉末烧结成形,且无明显的"球化"效应和翘曲变形.扫描电镜和X射线衍射分析证实,此组粉末体系的激光烧结是基于液相烧结机制,其中熔点较低的CuSn充当粘结金属,熔点较高的Cu充当结构金属;而添加元素P则起稀释剂的作用,能避免Cu颗粒表面氧化.研究了粉末体系中粘结金属含量对粉末烧结致密化和烧结件微观组织的影响.结果表明,在一定范围内粘结金属含量的提高有利于改善烧结致密度;但若粘结金属过量,则会因"球化"效应而降低致密度. 相似文献
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A. I. Kovalev V. P. Mishina D. L. Wainstein V. I. Titov V. F. Moiseev N. K. Tolochko 《Journal of Materials Engineering and Performance》2002,11(5):492-495
Presented is positive experience from selective laser sintering (SLS) of cylindrical steel specimens (3.0% C, 3.0% Cr, 1.0%
Si, 12.0% V, Fe balance) 30 mm long and 5 mm in diameter by rapid prototyping. It was demonstrated that monolithic steel material
could be successfully fabricated by this technology. Differential thermal analysis (DTA), scanning electron microscopy (SEM),
and x-ray diffractometry (XRD) were used to study the microstructure, phase, and chemical composition of the source material
and obtained specimens. Low-melting cementite-based eutectic was found to provide the liquid phase sintering of powder tool
steel. The porosity of the green sintered specimens did not exceed 5%. The mean hardness value of sintered specimens was 825
HV. 相似文献
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Rui-di LI Tie-chui YUAN Xiao-jun LIU Ji-wei WANG Hong WU Fan-hao ZENG Xiang ZHOU 《中国有色金属学会会刊》2017,27(7):1594-1601
The reaction diffusion between Fe and Al during spark plasma sintering (SPS) was studied. Microstructural evolution was investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) and the sintering kinetics was disclosed. The main interphase of the SPS sample was Fe2Al5 at 773–873 K. Ball-milling enabled a large number of lattice defects and grain boundaries thus the reaction kinetics was accelerated, although the direct current can also promote those defects. After milling, the phase transformation kinetics was improved from 0.207 before mill to 4.56×10?3. Besides, this work provided more details for the generation of Joule heating. The resistance offered to the electric path was considered to be the source of Joule heating, and particularly the resistance offered by the different contact interfaces of die, punch, graphite foil and the sample played a leading role for the generation of Joule heating during spark plasma sintering. 相似文献
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A type of polymer-coated molybdenum powder used in selective laser sintering technology was prepared by coating polymer on molybdenum particles and frozen grinding techniques, with the maximum particle diameter of 71 μm. The laser sintering experiments of polymer-coated molybdenum powder were conducted by using the self-developed selective laser sintering machine (HLRP-350I). The method of microscopic analysis was used to investigate the dynamic laser sintering process of polymer-coated molybdenum powder. Based on the study, the laser sintering mechanisms of polymer-coated molybdenum powder were presented. It is found that the mechanism is viscous flow when the laser sintering temperature is between 100 ℃ and 160 ℃, which can be described by a two-sphere model; and the mechanism is melting/solidification when the temperature is above 160 ℃. 相似文献
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制备一种用于激光烧结成形的包覆不锈钢粉末。应用数值模拟预测结合实际测量方法,研究激光功率、激光束扫描速度、预热温度及铺粉密度等参数对激光烧结深度的影响。结果表明,随着预热温度、铺粉密度与激光功率增加,烧结深度增加;随着扫描速度增加,烧结深度降低。但当扫描速度不超过2 mm/s时,烧结深度随扫描速度的增加反而增大。提出一种利用数值模拟预测结果进行激光烧结工艺参数选择的方法。 相似文献