章靖国
,
张小岷
,
林一坚
,
柯俊
,
陈兰英
金属学报
研究了经激光表面熔化处理的Fe-4％C-10％Sn合金的显微组织,发现在激光熔化区上部存在一种非晶相,而在其底部存在由α-Fe和一种bct相组成的显微组织,在熔化区其它区域存在含细小孪晶的马氏体。
关键词:
Fe-C-Sn合金
,
rapid solidification
,
laser
,
microstruture
张丹
,
满永发
,
刘金柱
材料研究学报
本文对激光快速熔凝Al-Li 合金进行了耐磨性实验研究,并对不同处理工艺下的耐磨性进行了比较。结果表明,不同处理工艺对耐磨性产生明显影响,但其均遵循同一微动磨损机制,即Al-Li 合金的组织结构对磨损机制没有影响;热轧态基材仅通过激光快速熔凝处理,耐磨性有所下降;但经激光快速熔凝+时效处理,耐磨性明显提高。
关键词:
Al—Li 合金
,
laser
,
rapid solidification
,
fretting
,
wear resistance
LI Ruiguo FENG Jun FENG Zhongchao Corrosion Science Laboratory.Institute of Corrosion and Protection of Metals. Academia Sinica
,
Shenyang
,
110015
,
ChinaInstitute of Metal Research
,
Academia Sinica.Shenyang 110015
,
China
材料科学技术（英文）
Silicon was added to the surface of 304 stain- less steel by laser melting the sprayed preplaced Si powders.The optical microscopy,X-ray diffraction and EPMA were employed to investigate the microstructure and chemical composition of the laser surface alloyed layer.The hardness of the al- loyed layer was measured by microhardness test and wear resistance was evaluated by scratch test. Corrosion resistance of laser alloyed sample was studied in 1N H_2SO_4+0.1N NaCl and 0.5N HCl+0.5N NaCl aqueous solutions.A microcrystalline intermetallic compound coating with smooth surface and good chemical homogeneity without porosity and crack is ob- tained.The hardness is about 720 HV.The wear re- sistance is 2 times better than that of the substrate. The corrosion resistance of the laser alloyed sample is much better than that of 304 stainless steel sample.
关键词:
laser
,
null
,
null
,
null
,
null
L. W. Zhang
,
J. Th.M.De Hosson
,
Y.L. Xia and F. G. Wang 1)The State Key Lab. for Materials Modification by Laser
,
Ion and Beams
,
Dalian University of Technology
,
Dalian 116023
,
China 2)Department of Applied Physics
,
University of Froningen
,
The Netherlands
金属学报(英文版)
In this paper,a thermal elastic-plastic 2-D finite element model of stress generation during laser transformation hardening process was developed. In this model, the mechanical properties of the material, Young's modules E, Poisson's ratio v, yield limit s, and thermal expansion coefficient α, are all change with temperature. The equivalent expansion method was used to deal with the problem with phase transformation. Based on this model, a program to calculate the residual stress field was developed using FORTRAN language. The residual stress fields in CO2 laser transformation hardened MoCu nodular iron were calculated. The calculated results showed that in the transformation hardened zone, the residual stress state is compress,whereas adjacent to this zone the residual stress state is tensile, and there is a tensile stress peak close to the transformation hardened zone. To verify this model, the residual stress fields were measured using X-ray diffraction method. The calculated results of residual stress fields are in good agreement with the experimental results.
关键词:
laser
,
null
,
null
,
null
,
null
Montasser M.Dewidar
,
Jae-Kyoo LIM
,
K.W.Dalgarno
材料科学技术（英文）
Layer manufacture technologies are gaining increasing attention in the manufacturing for the production of polymer mould tooling. Layer manufacture techniques can be used in this potential manufacturing area to produce tooling either indirectly or directly, and powder metal based layer manufacture systems are considered as an effective way of producing rapid tooling. Mechanical properties and accuracy are critical for tooling. This paper reports the results of an experimental study examining the potential of layer manufacturing processes to deliver production tooling for polymer manufacture. A comparison between indirectly selective laser sintering and directly selective laser sintering to provide the tooling was reported. Three main areas were addressed during the study: mechanical strength, accuracy, and build rate. Overviews of the results from the studies were presented.
关键词:
Selective laser sintering
,
laser
,
sintering
,
layer
,
manufact
LIANG Yong LI Ruiguo Institute of Metal Research
,
Academia Sinica
,
Shenyang 110015
,
ChinaInstitute of Corrosion and Protection of Metals
,
Aademia Sinica
,
Shenyang
,
110015
,
China
材料科学技术（英文）
Recent advances in laser coating technology including laser cladding,laser surface alloying and laser vapour deposition in China are reviewed in this paper.
关键词:
laser
,
null
,
null
,
null
,
null
ZHANG Jingguo ZHANG Xiaomin LIN Yijian Shanghai Iron and Steel Research Institute
,
Shanghai
,
ChinaKE Jun (T.Ko) University of Iron and Steel Technology Beijing
,
Beijing
,
ChinaCHEN Lanying Shanghai Institute of Optic and Fine Mechanics
,
Academic Sinica
,
Shanghai
,
China Senior Engineer
,
Shanghai Iron and Steel Research Institute
,
Shanghai 200940
,
China
金属学报(英文版)
The microstructure of a laser-melted Fe-4% C-10% Sn alloy has been studied.A non-crystalline phase was found in the upper part of the laser-melted zone:At the bottom of the melted zone,however,the microcrystalline zone which consists of α-Fe and a bet phase was observed.Fine twinning martensite exists in the other area of the melted zone.
关键词:
Fe-C-Sn alloy
,
null
,
null
,
null
何卫锋
,
李玉琴
,
李应红
,
李靖
,
聂祥樊
材料科学与工艺
为提高38CrMoAl钢渗氮层的质量和耐磨性能，提出并采用激光冲击增强渗氮的方法，进行了不同处理状态试样的磨损性能试验，采用XRD、SEM对试样微观组织进行分析，并探讨激光冲击增强渗氮的机理．试验结果表明：与渗氮相比，激光冲击波处理后渗氮试样的比磨损率为9．47×10－15m3／Nm，降低了50％，其表面显微硬度提高了12％；激光冲击波作用使表层材料产生高密度位错，甚至细化晶粒，从而在渗氮过程中增加了扩散通道，使更多的N原子间隙固溶到α－Fe中，对渗层起到了固溶强化的作用；形成的渗氮层微观组织致密，无缺陷，大量氮化物沿晶界高度弥散均匀分布，起到弥散强化的作用，从而提高了材料耐磨性能．
关键词:
激光
,
冲击波
,
渗氮
,
38CrMoAl钢
,
显微硬度
,
高密度位错
,
耐磨性能
