Critical instability at moving keyhole tip generates porosity in laser melting

doi:10.1126/science.abd1587

GSTDTAP > 气候变化

DOI	10.1126/science.abd1587
	Critical instability at moving keyhole tip generates porosity in laser melting
	Cang Zhao; Niranjan D. Parab; Xuxiao Li; Kamel Fezzaa; Wenda Tan; Anthony D. Rollett; Tao Sun
	2020-11-27
发表期刊	Science
出版年	2020
英文摘要	The formation of “keyholes” (vapor-filled depressions) during additive manufacturing leads to porosity, which degrades alloy performance, especially fracture properties, and remains a big challenge for the 3D printing of metals. Zhao et al. used high-speed x-ray imaging to take a detailed look at how keyhole formation connects to porosity in a titanium alloy. They found that instability at the keyhole tip drives pores away to get trapped in the solidification front. Understanding this process and the operating parameters under which it occurs provides a roadmap for avoiding porosity and building high-quality metal parts. Science , this issue p. [1080][1] Laser powder bed fusion is a dominant metal 3D printing technology. However, porosity defects remain a challenge for fatigue-sensitive applications. Some porosity is associated with deep and narrow vapor depressions called keyholes, which occur under high-power, low–scan speed laser melting conditions. High-speed x-ray imaging enables operando observation of the detailed formation process of pores in Ti-6Al-4V caused by a critical instability at the keyhole tip. We found that the boundary of the keyhole porosity regime in power-velocity space is sharp and smooth, varying only slightly between the bare plate and powder bed. The critical keyhole instability generates acoustic waves in the melt pool that provide additional yet vital driving force for the pores near the keyhole tip to move away from the keyhole and become trapped as defects. [1]: /lookup/doi/10.1126/science.abd1587
领域	气候变化 ; 资源环境
URL	查看原文
引用统计
文献类型	期刊论文
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/304882
专题	气候变化资源环境科学
推荐引用方式 GB/T 7714	Cang Zhao,Niranjan D. Parab,Xuxiao Li,et al. Critical instability at moving keyhole tip generates porosity in laser melting[J]. Science,2020.
APA	Cang Zhao.,Niranjan D. Parab.,Xuxiao Li.,Kamel Fezzaa.,Wenda Tan.,...&Tao Sun.(2020).Critical instability at moving keyhole tip generates porosity in laser melting.Science.
MLA	Cang Zhao,et al."Critical instability at moving keyhole tip generates porosity in laser melting".Science (2020).