Effect Of Laser Treatment On Microstructure And Mechanical Properties Of Zrticr Alloy

Zr alloys have been used in a number of industrial applications, because of their highstrength-to-weight ratio, high corrosion resistance, and relatively high melting temperature.However, further applications of Zr alloys are considerably restricted by their low surfacehardness and high friction coefficient. The purpose of this paper was to study the effects oflaser treatment on the structure and properties of zirconium-based alloys; the cross-flowCO2continuous wave laser was performed to provide high-density energy sources to treatthe ZrTiCr alloys with various scan rates. The microstructures and properties of the ZrTiCralloys were studied by using of experimental means.The structure evolution of ZrTiCr alloys was detected by X-ray diffraction and TEM.The structure of ZrTiCr alloys have phase α and phase β before laser surface treatment,and after laser treatment，the results showed that phase α and phase β content changed andthe enhanced phases named ω phase generated to some extent. After laser surface, the finegrain size in the melting area of the ZrTiCr alloys can be seen, through metallographicphotos. Use energy spectrum analysis, the local composition segregation was observed inthe ZrTiCr alloys with laser processing.The mechanical properties of ZrTiCr alloys before and after laser treatment werestudied by nanoindentation. The results showed that the nanohardness and elastic modulusof the sample after laser surface treatment improved from29.1%to106.1%and10.4%to31.2%, respectively. The depth and width of remelting area decreased with the laser scanrate increases.The friction coefficients of the ZrTiCr alloys after laser treatment decrease from0.35to about0.20, the rate is about40%. At the same conditions, corrosion current is0.489μAbefore laser treatment, the corrosion current reduced about50%after laser treatment, thecorrosion resistance is improved.