Mn对电弧增材N50组织与低温性能的影响

Effect of Mn on the microstructure and cryogenic mechanical properties of N50 stainless steel fabricated by TIG additive manufacturing

N50不锈钢具有优异的低温性能,有希望应用于磁约束核聚变线圈盒的结构中。为提高材料利用率,本文利用TIG增材工艺制造N50不锈钢,研究Mn含量对电弧增材组织与液氮温区(77 K)力学性能的影响。从物相组成、微观组织、夹杂物等角度分析了Mn对低温力学性能的影响规律。研究结果表明:Mn元素对材料低温塑韧性产生较明显的影响,Mn含量升高造成77 K下N50不锈钢的断后伸长率从28%降低至24%,冲击韧性从11.0 J降低至3.6 J。

N50 stainless steel has excellent cryogenic properties and is promising for application in the structure of nuclear fusion.In order to improve the material utilization,the TIG additive manufacturing was used to fabricate N50 stainless steel,the effects of Mn content on the microstructure and the mechanical properties of N50 were investigated in the temperature region of liquid nitrogen(77 K).The influence of Mn on the cryogenic mechanical properties was analyzed from the perspectives of phase composition,microstructure and inclusions.The results show that the Mn element has a obvious effect on the cryogenic plastic toughness of the material,and the increase in Mn content causes the elongation at break of N50 stainless steel to decrease from 28%to 24%at 77 K,and the impact toughness to decrease from 11.0 J to 3.6 J.