• CN:11-2187/TH
  • ISSN:0577-6686

机械工程学报 ›› 2020, Vol. 56 ›› Issue (3): 189-196.doi: 10.3901/JME.2020.03.189

• 制造工艺与装备 • 上一篇    下一篇

异种材料激光选区熔化界面结构强化机理研究

刘林青, 宋长辉, 杨永强, 翁昌威   

  1. 华南理工大学机械与汽车工程学院 广州 510641
  • 收稿日期:2019-03-15 修回日期:2019-10-09 出版日期:2020-02-05 发布日期:2020-04-09
  • 通讯作者: 宋长辉(通信作者),男,1986年出生,副教授,硕士研究生导师。主要研究方向为陶瓷、金属3D打印与个性化医学。E-mail:chsong@scut.edu.cn
  • 作者简介:刘林青,男,1996年出生。主要研究方向为激光选区熔化快速成型技术。E-mail:1225483738@qq.com
  • 基金资助:
    国家自然科学基金(51705160)、广东省科技项目(2017B090912002,2017A030313271,2015B090921002)和广州市产学研专项201704020118)资助项目。

Study on Mechanism of Strengthening Interface Structure of Dissimilar Materials by Selective Laser Melting

LIU Linqing, SONG Changhui, YANG Yongqiang, WENG Changwei   

  1. School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510641
  • Received:2019-03-15 Revised:2019-10-09 Online:2020-02-05 Published:2020-04-09

摘要: 为了将成形精度高、效率慢的激光选区熔化技术(Selective laser melting,SLM)应用于大型复杂结构件生产制造过程中,可在传统机加工基体上SLM成形精密复杂结构。然而不同材料、不同制造工艺的结构在界面处的结合性能制约着整体结构的性能。本研究在机加工制造的低成本Cr8Mo2SiV冷作模具钢上SLM成形18Ni300马氏体时效钢。通过金相显微镜、扫描电镜等对界面结合区域的组织结构以及成分分析,发现界面处增材结构(18Ni300)紧密镶嵌在基材结构(Cr8Mo2SiV)中,形成类似一种齿形镶嵌的结构。界面区域无宏观裂纹产生,表明SLM结构与基材达到良好的冶金结合。在界面区域观察到柱状晶穿过熔道边界外延生长,且界面元素有稍许扩散。分析表明,界面区域的齿形镶嵌结构以及柱状晶的外延生长形态有利于界面结构的结合强化。通过拉伸试验进行结合性能分析,发现整体复合结构拉伸件的断裂位置处于远离界面的基材处,且在界面区域得到明显强化效果,这为高效低成本制作复杂模具提供了有效方法。

关键词: 激光选区熔化, 异种材料, 马氏体时效钢, 界面结合, 微观结构和性能

Abstract: In order to apply the selective laser melting(SLM) technology with high precision and low efficiency to the manufacturing process of large-scale complex structural parts, sophisticated complex structure can be fabricated by selective laser melting on the traditional machined substrate. However, the bonding performance of the structure with different materials and different manufacturing processes at the interface restricts the performance of the overall structure. In this study, 18Ni300 maraging steel is fabricated by SLM on traditional low-cost Cr8Mo2SiV cold work die steel manufactured by machining method. The microstructure and composition analysis of the interface bonding region are observed by metallographic microscope, scanning electron microscope, etc., and it is found that the additive structure (18Ni300) at the interface is tightly embedded in the substrate structure (Cr8Mo2SiV) to form a structure similar to a toothed mosaic. There is no macro crack in the interface area, and the SLM structure and the substrate achieve a good metallurgical bonding. It is observed in the interface region that the columnar crystals were epitaxially grown through the boundary of the melt channel, and the interface elements are slightly diffused. The analysis shows that the toothed mosaic structure of the interface region and the epitaxial growth morphology of the columnar crystal facilitate the bonding enhancement of the interface structure. Through the analysis of the bonding performance by the tensile testing, it is found that the fracture position of the composite structure tensile specimen is located at the substrate away from the interface, and the obvious strengthening effect is obtained in the interface area, which provides an effective method for efficient and low-cost production of complex molds.

Key words: selective laser melting, dissimilar materials, maraging steel, interface bonding, microstructure and properties

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