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研究了块体Zr55Al10Ni5Cu30非晶合金在脉冲激光重熔下的组织演化行为。激光熔凝区始终保持非晶结构,热影响区(HAZ)在激光能量密度大或者扫描速度慢时晶化倾向大,扫描速度≥15 mm/s时可避免晶化,但发生结构弛豫过程。热影响区非晶部分晶化时,晶化为内部具有层状共生生长结构的球状晶粒,晶化尺度为微米级,晶化相由四方相Zr2Cu及面心立方相Zr2Ni组成。熔池底部位置的热影响区较熔池靠近表面边缘晶化严重。熔池底部热影响区的晶粒尺寸随远离熔凝区逐渐变小,且晶粒内部的层数在热影响区呈现靠近熔凝区侧多于靠近基材侧的趋势。
The microstructure evolution of bulk Zr55Al10Ni5Cu30 amorphous alloy under pulsed laser remelting was studied. The laser fusion zone always has an amorphous structure. The heat-affected zone (HAZ) has a large tendency of crystallization when the laser energy density is high or the scanning speed is slow. When the scanning speed is greater than or equal to 15 mm / s, crystallization can be avoided, but structural relaxation occurs . When the amorphous part of the heat-affected zone is crystallized, it is crystallized into spherical grains with a layered intergrowth structure inside. The crystallization scale is on the order of micrometers, and the crystallization phase consists of tetragonal Zr2Cu and face-centered cubic Zr2Ni. The heat affected zone at the bottom of the molten pool is more heavily crystallized than the molten pool near the edge of the surface. The grain size of HAZ at the bottom of the molten pool decreases with the distance from the melting zone, and the number of layers inside the grain tends to be closer to the melting zone than to the substrate in the HAZ.