通过调整脉冲波直接能量沉积,综合控制热残余应力和机械性能
Zhou Yan1,2,3,4, Jia Guo2,3,5, Xi Zou4
1School of Information Engineering, Hubei University of Economics, Wuhan 430205, China.
Materials (Basel, Switzerland)
|November 9, 2024
概括
脉冲波激光沉积显著降低了316L不钢部件的残余应力和热裂纹. 这种增材制造技术通过控制温度梯度来最大限度地减少热裂纹的形成,从而改善机械性能.
科学领域:
- 材料科学 材料科学 材料科学
- 添加剂制造 添加剂制造 添加剂制造
- 激光处理 激光加工
背景情况:
- 激光束定向能量沉积 (DED-LB) 工艺,特别是316L不钢,容易产生显著的残余应力.
- 这些压力源于快速加热和冷却周期,可能导致沉积元件的裂和服务故障.
研究的目的:
- 通过使用连续波 (CW) 和脉冲波 (PW) 激光模式,对316L不钢在DED-LB过程中应变和温度梯度的现场演变进行调查.
- 分析激光模式对热裂纹形成和几何位移密度的影响.
- 确定PW激光沉积如何减轻残余应力并增强机械性能.
主要方法:
- 利用数字图像相关性 (DIC) 在现场应变测量.
- 采用热成像来监测沉积层中的温度梯度.
- 检查了热裂纹特性和几何位移密度.
- 使用CW和PW激光模式进行DED-LB性能比较.
主要成果:
- 与CW模式相比,PW模式导致较低的温度梯度和减少的热应变.
- CW模式导致样品进入"脆性温度区域",导致大量的热裂.
- 在PW模式的样本中,裂显著减少,避免了对裂敏感的固化区域.
- 在PW激光沉积过程中,残余应力降低,机械性能改善.
结论:
- 脉冲波激光沉积在316L不钢的增材制造过程中有效地减少了热裂纹的形成.
- 通过PW模式控制温度梯度对于减少热应变和防止裂纹开始至关重要.
- 激光加工提供了一个可行的策略,以提高DED-LB组件的机械完整性和可靠性.
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