利用激光增材制造技术, 在钛合金基体表面制备氧化铝增强镍基合金涂层。分析了柱状晶的生长过程, 在增材制造合金件过程中, 顶部会形成一层等轴晶, 而内部柱状晶会穿过多层沉积层外延生长。当激光功率为1 500 W时, 组织相主要为短小柱状晶, 当激光功率增大时, 短小柱状晶逐渐变成细长柱状晶, 同时柱状晶粒宽度尺寸也相应变大。当扫描速率V从0.6 m/min梯度变化到1.2 m/min时, 柱状晶的尺寸宽度也随之减小。此外可通过控制扫描速率来定向调节柱状晶的形成角度。

The alumina-reinforced Ni-based alloy coating was prepared on the surface of the titanium alloy substrate by laser additive manufacturing.The growth process of the columnar crystals is analyzed.The equiaxed crystal is formed at the top, and the internal columnar crystal will grow through the multi-layer sedimentary layer.The laser power is 1 500 W, the microstructure is mainly composed of short columnar crystals and the short columnar crystals gradually become elongated columnar crystals. The columnar grain width size becomes larger with the laser power increases. When the scanning rate V varies from 0.6 m/min to 1.2 m/min, the size of the columnar crystal is also reduced. In addition, the formation angle of the columnar crystals can be adjusted by controlling the scanning rate.