S.Y. Gao
,
Y.Z. Zhang
,
L.K. Shi
,
B.L. Du
,
M.Z. Xi
,
H.Z. Ji
,
null
,
null
,
null
,
null
,
null
,
null
,
null
,
null
,
null
,
null
,
null
金属学报(英文版)
Laser direct deposition (LDD) of metallic components is an advanced technology of combining CAD/CAM (computer aided design/computer aided manufacturing), high power laser, and rapid prototyping. This technology uses laser beam to melt the powders fed coaxially into the molten pool by the laser beam to fabricate fully dense metallic components. The present article mainly studies the LDD of Ti-6Al-4V alloy, which can be used to fabricate aircraft components. The mechanical properties of the Ti-6Al-4V alloy, fabricated by LDD, are obtained using the tension test, and the oxygen content of used powders and deposited specimens are measured. In the present article, it can be seen that the mechanical properties obtained using this method are higher than the ones obtained by casting, and equal to those got by wrought anneal. One aircraft part has been made using the LDD process. Because of this aircraft part, with sophisticated shape, the effect of the laser scanning track on the internal soundness of the deposited part was discussed.
关键词:
laser direct deposition
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null
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null
张志波
,
张红斌
,
张瑜
,
杨春雷
,
张卫强
,
李金柱
钢铁
研究了在昆钢特有的双机架紧凑式炉卷轧机上开发和生产高强度汽车大梁钢K610L的工艺。通过合理的Nb-Ti复合成分设计和各工序生产工艺试验与优化,生产出满足重型载货汽车制造厂要求的K610L高强度汽车大梁钢。结果表明,昆钢利用炉卷轧机生产的K610L具有较高的抗拉强度、良好的韧性、优异的冷弯成型性能和较好的自然时效性。
关键词:
炉卷轧机
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高强度汽车大梁钢
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Nb-Ti复合
NI Hongwei
,
HE Hang
,
LI Guangqiang
,
LIU Jing
钢铁研究学报(英文版)
Preparation of nanocrystalline 430L stainless steel by both highenergy ball milling and spark plasma sintering technique has been investigated. The results have shown that the hardness can be improved markedly with an increase in sintering temperature and holding time. The lower the apparent porosity of nanocrystalline 430L stainless steel, the higher is the Vickershardness. The tensile strength reached a maximum value of 713 MPa when the sample was sintered at 1 173 K for 10 min, and then it evidently decreased with an increase in sintering temperature and holding time because of the growth of crystalline grain.
关键词:
ferritic stainless steel;nanocrystalline;spark plasma sintering
尹晓燕
,
初乃波
,
赵庆宇
,
王金渠
,
鲁金明
硅酸盐通报
采用水热合成法成功合成出高结晶度的L沸石.合成初始凝胶(物质的量)组成为5.4K2O:5.7Na2O:1Al2O3:30SiO2:500H2O,反应温度为175℃,反应时间为24 h.采用X射线衍射(XRD)、扫描电镜(SEM)对合成的沸石分子筛进行了表征.XRD检测结果表明:制备的沸石具有L沸石典型特征峰,结晶度较高.SEM检测结果表明:合成的L沸石分子筛呈圆柱状,粒径约为1 μm,大小均匀.由于L沸石晶化区间相对狭窄,合成过程中须严格控制反应条件,所以又全面考察了水热合成条件对L沸石晶化的影响,结果表明:nSiO2/nAl2O3、Nh2o/n(Na2O+K2O)、nNa2O/n(Na2O+K2O)对结晶过程影响很大;陈化可以较好地减小晶粒尺寸,增加晶粒均匀度.
关键词:
L沸石
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水热合成
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晶化
梁成浩
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郭承忠
材料保护
doi:10.3969/j.issn.1001-1560.2007.10.007
采用正交试验法对无氰电镀22K金工艺进行了优选,并利用X射线荧光光谱仪、分光色彩精灵、金相显微镜、显微硬度计等检测了镀层表面的金含量、表面光泽度、表面形貌及镀层厚度、显微硬度等性能.结果表明,无氰电镀22 K金优化的工艺参数:160 g/L亚硫酸钠,120 g/L柠檬酸钾,30 g/L硫酸钴,9 g/L亚硫酸金钠(以金计),40～50 g/L磷酸氢二钾,10 g/L添加剂A,施镀温度45～55℃,阴极电流密度0.18～0.25 A/dm3,pH值8.5～9.5,阴、阳极面积比1:3,搅拌方式为阴极移动.在优化工艺下所得的22K金镀层呈金黄色、均匀、细致、半光亮,具有较好的结合力、耐蚀性和较高的显微硬度,可作装饰性镀层.
关键词:
无氰
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电镀
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金合金
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22K金
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工艺
Zhong CHU
材料科学技术（英文）
Simulations are performed on temporal evolution of atom morphology and ordering parameters of Ni-14.5 Cr-16.5 Al alloy during early precipitation process at different temperatures based on microscopic phase-field theory; the relationship between precipitation sequence and mechanism of L12 and D022 structure and precipitation temperature are illuminated. The nonstoichiometric ordered L12 phases appear first with congruent ordering+spinodal decomposition mechanism which is then followed by precipitation of D022 phases at ordering domain boundaries of L12 phases by spinodal decomposition mechanism at 1073 K and 1223 K. The nonstoichiometric L12 phases transform to stoichiometric ordering phases gradually. The incubation period of L12 and D022 phases is shorter at 1073 K than that 1223 K, and growth speed is higher at 1073 K. At 1373 K, L12 and D022 phases appear simultaneously by non-classical nucleation and growth mechanism. After that the particles of D022 phases diminish and disappear gradually; L12 phases grow and single L12 phases are remained at last.
关键词:
Ni-Cr-Al
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微观相场
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沉淀
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序参数
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模拟
