中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 25 No. 5 May 2015 |
（1. College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China;
2. Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education,
Taiyuan University of Technology, Taiyuan 030024, China）
Abstract:Laser surface melting (LSM) is a high-energy surface treatment that allows modification of the microstructure and surface properties of Mg alloys. In the present work, an attempt of LSM on magnesium alloy with liquid nitrogen-assisted cooling (LNSC) was carried out to get the higher cooling rate and improve the surface properties. The experimental results were compared with those of Ar gas protection at room temperature. The samples after LSM with LNSC resulted in a thinner melted layer, a highly homogeneous, refined melted microstructure and formed a lot of worm-like nanocrystals and local amorphous structures. Microhardness of the melted layer with LNAC was improved to HV 90-148 as compared to HV 65-105 of the samples with Ar gas protection. The corrosion resistance of the melted layer in a 3.5% NaCl solution (mass fraction) was improved because of the grain refinement and redistribution of β-Mg17Al12 phases following rapid quenching associated with the process.
Key words: magnesium alloy; laser surface melting; liquid nitrogen-assisted cooling; microhardness; corrosion resistance
