论文标题
超声辅助添加剂制造中不锈钢的谷物精炼
Grain refinement of stainless steel in ultrasound-assisted additive manufacturing
论文作者
论文摘要
由基于融合的添加剂制造（AM）或3D打印制造的金属和合金经历了复杂的熔化和固化动力学，对有效控制谷物结构的控制构成了挑战。在此，我们报告了使用高强度超声检查，该超声控制在316升不锈钢的AM期间控制固化过程。我们发现，超声的使用有利于柱状到等式的过渡，从而促进了具有随机晶体纹理的细含量晶粒的形成。此外，尽管在AM期间冷却速率和温度梯度降低，但超声的使用将晶粒的数量密度从305 mm-2增加到2748 mm-2。我们对晶粒尺寸和冷却速率之间关系的评估表明，超声会增强AM期间的微晶形成。此外，超声的使用通过降低大部分熔体池中的温度梯度来增加固化过程中的宪法过冷的量，从而创造了一种有利于晶粒成核，生长和存活的环境。这种新的理解提供了更好地利用超声检查以控制AM制作金属产品中的谷物结构的机会。
Metals and alloys fabricated by fusion-based additive manufacturing (AM), or 3D printing, undergo complex dynamics of melting and solidification, presenting challenges to the effective control of grain structure. Herein, we report on the use of high-intensity ultrasound that controls the process of solidification during AM of 316L stainless steel. We find that the use of ultrasound favours the columnar-to-equiaxed transition, promoting the formation of fine equiaxed grains with random crystallographic texture. Moreover, the use of ultrasound increases the number density of grains from 305 mm-2 to 2748 mm-2 despite an associated decrease in cooling rate and temperature gradient in the melt pool during AM. Our assessment of the relationship between grain size and cooling rate indicates that the formation of crystallites during AM is enhanced by ultrasound. Furthermore, the use of ultrasound increases the amount of constitutional supercooling during solidification by lowering the temperature gradient in the bulk of the melt pool, thus creating an environment that favours nucleation, growth, and survival of grains. This new understanding provides opportunities to better exploit ultrasound to control grain structure in AM-fabricated metal products.
