采用同步送粉方式激光立体成形Zr55Cu30Al10Ni5块体非晶合金, 研究了不同脉宽下(2.5, 5, 10 ms)激光立体成形块体非晶合金的晶化特征。实验结果表明, 3个试样熔覆层大部分为非晶态, 非晶基材上出现宽厚的晶化带, 而且熔池底部热影响区比熔池侧面热影响区晶化严重。由于粉末的氧含量比基材中的高, 5 ms和10 ms试样基材顶部晶粒团簇成片, 基材底部晶粒呈离散分布, 2.5 ms试样整个基材的晶粒为离散分布。单点能量密度一定时, 过长的脉宽可使热影响区的升降温速率减小, 晶化较严重。反之, 脉宽越短, 即使粉末氧含量较高, 晶化无明显恶化。

The Zr55Cu30Al10Ni5bulk metallic glasses (BMGs) were prepared by Laser solid forming (LSF) using synchronous powder feeding method. The crystallization characteristics during LSF of BMGs with different pulse duration (2.5 ms, 5 ms, 10 ms) were investigated. It was found that the deposits were mainly constituted by amorphous, but the thick crystallization bands were formed in the amorphous substrates, and the crystallization extent of heat affected zone (HAZ) at the bottom of melt zone is more serious than the side. For 5 ms and 10 ms specimens, there were the grain clusters appeared at the top of substrate and the grains distribution separately at bottom of the substrate since the oxygen content of the powder is higher than the substrate. The grain dispersed distribution in the whole substrate of 2.5 ms specimen. For the certain single energy density, the longer pulse durations would slow down the heating and cooling rate in HAZ, so that crystallization is more severe. Conversely, the shorter the pulse width, the crystallization had no significant deterioration even if the higher oxygen content of the powder.