Key Laboratory of Interface Science and Engineering in Advanced Materials of Ministry of Education

Taiyuan, China

Key Laboratory of Interface Science and Engineering in Advanced Materials of Ministry of Education

Taiyuan, China
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Gan Y.,Taiyuan University of Technology | Gan Y.,Key Laboratory of Interface Science and Engineering in Advanced Materials of Ministry of Education | Wang W.,Taiyuan University of Technology | Wang W.,Key Laboratory of Interface Science and Engineering in Advanced Materials of Ministry of Education | And 8 more authors.
Optik | Year: 2015

Abstract During the laser surface melting (LSM) of AZ31B Mg alloy, obtaining desired temperature field distribution is essential for production goal and reliable service performance. In this study, a 3D finite element model was developed to analyze the thermal characteristics during the diode laser surface melting of Mg alloy with different process parameters. The simulation visually predicts the great temperature gradient and fast cooling speed during LSM. The microstructure of the fusion zone was observed to validate the accuracy of the simulation. Verification experiment based on infrared temperature measurement (ITM) was applied. By comparing the maximum temperature values, the average heating and cooling rate and the dimension of the melt pool with various laser powers and scanning speed, the simulation results are in good agreement with the experimental measurements. © 2015 Elsevier GmbH. All rights reserved.


Cui Z.,Taiyuan University of Technology | Cui Z.,Key Laboratory of Interface Science and Engineering in Advanced Materials of Ministry of Education | Li Y.,Taiyuan University of Technology | Wang W.,Taiyuan University of Technology | And 3 more authors.
Chinese Optics Letters | Year: 2015

We investigate the influence of environmental media on ablation rate of AISI 443 stainless steel under femtosecond (fs) laser single raster scan and multiple raster scans in air, water, and methanol. Meanwhile, the development of ablation rate with the change of fs laser-induced surface morphology in the three environmental media is comparatively studied. The results show that environmental media as well as fs laser-induced morphology control the ablation rate with the increasing number of raster scans (N). Under single raster scanning (N = 1), the ablation rate is higher in liquid than in air due to the confinement of plasma, laser-induced shockwaves, and bubble-related mechanical forces. However, under multiple raster scans, the variation in ablation rate with the increase in N in these three environmental media is complicated and is largely determined by the surface morphology induced by previous fs laser ablation. When N > 20, the ablation rate is much higher in air than in liquids due to preferential ablation caused by the formation of nanostructures-textured mound-shaped microstructures in air. Besides, the redeposition of ejected ablated materials is also an important factor that affects the ablation depth. © 2015 Chinese Optics Letters.


Wang W.,Taiyuan University of Technology | Wang W.,Key Laboratory of Interface Science and Engineering in Advanced Materials of Ministry of Education | Chen J.,Taiyuan University of Technology | Chen J.,Key Laboratory of Interface Science and Engineering in Advanced Materials of Ministry of Education | And 5 more authors.
Zhongguo Jiguang/Chinese Journal of Lasers | Year: 2011

Surface of AZ31B magnesium alloy is melted using a pulsed Nd:YAG laser in liquid nitrogen. Then the laser melted layer cooled in liquid nitrogen is compared with that cooled in air and the substrate. The results show that the grain size of the laser melted layer cooled in liquid nitrogen is smaller than that cooled in air. The laser melted layer cooled in liquid nitrogen has higher micro-hardness (70~77 HV0.05) than that cooled in air(60~67 HV0.05) compared with the as-received magnesium alloy (about 55 HV0.05). The wear mass loss of the laser melted layer cooled in liquid nitrogen (1 × 10-3 g) is less than that cooled in air (2 × 10-3 g). The results indicate that liquid nitrogen is better for the enhancement of wear resistance of the laser melted layer. The experimental results show that the corrosion potential of the laser melted layer cooled in liquid nitrogen and cooled in air decrease by 22 mV and 29 mV than those of the as-received magnesium alloy respectively. This indicates that corrosion resistance of AZ31B magnesium alloys becomes worse by laser surface melting.


Zhang J.-L.,Taiyuan University of Technology | Zhang J.-L.,Key Laboratory of Interface Science and Engineering in Advanced Materials of Ministry of Education | Wang G.-J.,Taiyuan University of Technology | Liu L.,Taiyuan University of Technology | And 4 more authors.
Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment | Year: 2011

Effects of heat treatment on microstructure and mechanical properties of AM60-0.3Nd magnesium alloy were investigated by means of optical microscopy, SEM, XRD and tensile test. The results indicate that grain size of the AM60-0.3Nd alloy decreases from 90 μm in as-cast condition to about 20 μm after T4 heat treatment and the net-like β-Mg17Al12 distributed along grain boundary disappears completely. The dot and block AL-Nd intermetallics change to spherical ones and tensile strength increases to 262 MPa for the as-cast AM60-0.3Nd alloy after T4 heat treatment. After T6 heat treatment, the grain size of AM60-0.3Nd is refined to about 30 μm and β-Mg17Al12 phases are re-precipitated, and the spherical Al-Nd intermetallics change to the block again and its hardness increases significantly, reaching to 75 HV.

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