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超声振动辅助激光熔化沉积316L不锈钢的微观组织演变研究
引用本文:柴鹏涛,刘学,李晋锋,刘政豪,杨晓珊,周昱昭,王小英,董鲜峰,乐国敏. 超声振动辅助激光熔化沉积316L不锈钢的微观组织演变研究[J]. 稀有金属材料与工程, 2020, 49(12): 4177-4184
作者姓名:柴鹏涛  刘学  李晋锋  刘政豪  杨晓珊  周昱昭  王小英  董鲜峰  乐国敏
作者单位:中国工程物理研究院材料研究所,中国工程物理研究院材料研究所,中国工程物理研究院材料研究所,中国工程物理研究院材料研究所,中国工程物理研究院材料研究所,中国工程物理研究院材料研究所,中国工程物理研究院材料研究所,中国工程物理研究院材料研究所,中国工程物理研究院材料研究所
基金项目:国家重点研发计划(2017YFB0702400);国家自然科学基金资助(项目号51871203,11605164)
摘    要:在激光熔化沉积316L不锈钢的过程中耦合不同功率的超声振动,研究了超声功率对晶粒形态尺寸、凝固组织形成机制以及晶粒生长特性的影响。研究表明,激光熔化沉积过程中316L不锈钢晶粒发生定向凝固外延生长,形成粗大的柱状晶。施加超声会将沿[100]方向外延生长的粗大原生柱状晶打碎,产生细化晶粒的效果;沿柱状晶外延生长方向传递的超声振动增大了晶粒内沿长轴方向的累积取向差,提高了平均位错密度。施加超声有助于加强熔池流体的对流,降低沿沉积方向的温度梯度,使得垂直生长的柱状晶更快转变为八字形柱状晶;同时提高合金凝固冷速,使得柱状晶宽度以及晶粒内部一次枝晶列间距减小,实现宏观晶粒尺寸与微观枝晶间距的细化。

关 键 词:超声振动  激光熔化沉积  316L不锈钢  晶粒形态  晶粒尺寸  凝固方式
收稿时间:2019-12-25
修稿时间:2020-04-09

Microstructural Evolutions of 316L Stainless Steel Prepared by Ultrasonic Vibration Assisted Laser Melting Deposition
Chai Pengtao,Liu Xue,Li Jinfeng,Liu Zhenghao,Yang Xiaoshan,Zhou Yuzhao,Wang Xiaoying,Dong Xianfeng and Le Guomin. Microstructural Evolutions of 316L Stainless Steel Prepared by Ultrasonic Vibration Assisted Laser Melting Deposition[J]. Rare Metal Materials and Engineering, 2020, 49(12): 4177-4184
Authors:Chai Pengtao  Liu Xue  Li Jinfeng  Liu Zhenghao  Yang Xiaoshan  Zhou Yuzhao  Wang Xiaoying  Dong Xianfeng  Le Guomin
Affiliation:Institute of Materials,China Academy of Engineering Physics,Institute of Materials,China Academy of Engineering Physics,Institute of Materials,China Academy of Engineering Physics,Institute of Materials,China Academy of Engineering Physics,Institute of Materials,China Academy of Engineering Physics,Institute of Materials,China Academy of Engineering Physics,Institute of Materials,China Academy of Engineering Physics,Institute of Materials,China Academy of Engineering Physics,Institute of Materials,China Academy of Engineering Physics
Abstract:Ultrasonic vibrations with ultrasonic powers of 0 W, 600 W, 1000 W and 1400 W were applied during laser melting deposition of 316L stainless steel. The effects of ultrasonic powers on the grain morphologies and sizes, the microstructure formation mechanism and grain growth characteristics of 316L stainless steel were studied. The results show that the application of ultrasonic vibrations can break the directional epitaxial growth of large sized columnar grains, resulting in a refinement of microstructure, and increases of cumulative misorientation and dislocation densitie along the long axis of grains. By promoting the convections in the melt pool, and thus reducing the temperature gradient along the depostion direction, the application of ultrasonic vibrations accelerate the transitions of growth directions for columnar grains. The application of ultrasonic vibrations also help to increase the cooling rate during solidification, resulting in refinements of both columnar grains and the interior columnar dendrites.
Keywords:Ultrasonic vibration   laser melting deposition   316L stainless steel   Grain morphology   Grain size   Solidification mode.
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