中国机械工程

• 先进材料加工工程 • 上一篇    下一篇

DD5镍基单晶高温合金铣削亚表面损伤研究

李强;郭辰光;丁广硕;冷岳峰;岳海涛   

  1. 辽宁工程技术大学机械工程学院,阜新,123000
  • 出版日期:2020-11-10 发布日期:2020-11-16
  • 基金资助:
    辽宁省科技厅博士启动基金资助项目(20180540042);
    辽宁省自然科学基金资助项目(20180550167);
    辽宁省教育厅资助重点项目(LJ2019JL005);
    辽宁省教育厅基础研究项目(LJ2019JL003)

Research on Milling Subsurface Layer Damages of  DD5 Ni-based Single Crystal Superalloy

LI Qiang;GUO Chenguang;DING Guangshuo;LENG Yuefeng;YUE Haitao   

  1. School of Mechanical Engineering, Liaoning Technical University, Fuxin, Liaoning, 123000
  • Online:2020-11-10 Published:2020-11-16

摘要: 为探究DD5镍基单晶高温合金铣削亚表面损伤特征,基于定向切割方法及槽铣实验,通过对热处理前后不同铣削参数条件下DD5纵截面微观金相结构的观测及维氏硬度检测,对被加工材料变形层特征和再结晶行为进行研究,并提出了相应的抑制方法。结果表明,铣削参数、冷却方式及晶向条件对DD5表面硬化率具有重要影响,其表面沿法向方向的硬度变化趋势为“硬化—软化—硬化”,说明在热软化和应变硬化的竞争机制下铣削变形层是由应变硬化造成的,且该区域发生了金相组织变化,提高了材料的抗腐蚀能力;沿[110]晶向进行切削轨迹规划及采用水基微量润滑对变形层的抑制是有益的;在所设计的各种工艺参数条件下,铣削加工过程无法提供足够的形变储存能来促进DD5在1300 ℃的传统和真空热处理条件下再结晶的发生。

关键词: 镍基单晶高温合金, 铣削亚表面, 变形层, 加工硬化, 再结晶

Abstract: In order to research the milling subsurface layer damages of DD5 Ni-based single crystal superalloy, based on the directional cutting method and slot milling experiments, this paper discussed the DD5 deformation layer characteristics and recrystallization behaviors though the massive DD5 longitudinal sections micro-metallographic structures and micro-hardness tests under different milling parameters before and after heat treatments. Then the control approaches for inhibiting the deformation layer generation and development were proposed. The research results demonstrate that milling parameters,cooling methods and crystal direction conditions all influence the DD5 hardening rate largely, the hardness of the machined surface along the normal direction show the “hardening-softening-hardening”trend, which illustrate that the main reason for metamorphic layer formation is work hardening under the competition mechanism between the thermal softening and strain hardening, and the metallographic structure in this area is transformed, which improve the corrosion resistance of DD5 machined surfaces. The reasonable milling trajectory along the [110] crystal direction scheme and the water based minimum quantity lubrication adoption of cooling methods are beneficial for the inhibition of deformation layer formation. In addition, under the machining conditions designed herein, the milling processes may not provide sufficient stored energy to activate material recrystallization under the traditional and vacuum high temperature conditions to 1300℃.

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