A pulsed Nd∶YAG laser was used to modify the surface properties of heat-resistant and high-strength Mg-Gd wrought magnesium alloys with precursor of TiB2 ceramic micro powders and Al powders as the binders. The samples were prepared with different compositions of the precursor in order to understand the effect of TiB2 on the alloying coating. The micro-fine structure

phases constituent and micro-hardness

wear and corrosion resistance of the laser-alloyed layer with different TiB2 content were characterized by SEM （scanning electron microscope）

XRD（X-ray diffraction）

TEM

micro-hardness tester

abrasion testing machine and the Zahner IM6ex electrochemical workstation

respectively. The results show that the in-situ reaction occurs in the alloyed layer between Al and elements of Gd and Y in Mg alloy matrix

and the intermetallic compounds such as Al2Gd and Al2Y with excellent high temperature stability are generated. Meanwhile

the absence of the decomposition of the strengthening phase TiB2 can be observed. The particle size of in-situ synthesized intermetallic compounds and the reinforced phases is about 100 nm and 200 nm

respectively

and they exhibit good compatibility and uniform distribution. However

significant difference in the characteristics of distribution and structures are observed. The overall micro-hardness of the alloyed layer is increased with the increase of TiB2 content and improved up to 4

6

times of the substrate. However

the friction coefficient and wear weight loss indicate the opposite variation tendency. Compared with the magnesium alloy substrate

the corrosion resistance of the laser surface alloyed samples is improved significantly within a certain range of the composition ratio.