中国激光, 2021, 48 (3): 0315001, 网络出版: 2021-02-23   

纳米TiC改性对选区激光熔化铜成形的影响 下载: 900次

Effect of Nano-TiC Modification on Selective Laser Melting of Copper
作者单位
昆明理工大学材料科学与工程学院, 云南 昆明650093
摘要
为减少选区激光熔化铜成形过程中铜粉对激光的反射,提高激光吸收率和成形件致密度,通过机械球磨使用具有高激光吸收率的纳米TiC对粒径为15~53 μm的铜粉进行改性。结果表明:改性后的铜粉对激光的吸收率由22%提高到53.7%;在激光功率为340 W、扫描速度为500 mm/s条件下成形的试样,其致密度由改性前的90.7%提高到99.8%。采用纳米TiC对铜粉进行改性,实现了铜粉对激光吸收率的大幅度提升和小功率激光扫描条件下选区激光熔化高致密铜的成形。
Abstract

Objective With its excellent thermal conductivity, copper is an ideal material for the critical complex cooling parts in the combustion chambers of aerospace engines. Increasingly, complex copper parts are being fabricated by selective laser melting, an additive manufacturing method that forms complex 3D parts and structures. However, bulk copper surfaces and spherical copper particles absorb less than 10% and 45% of 1064 nm laser energy, respectively. Melting the copper powder completely and fabricating sound copper parts without defects such as unmelted particles and holes are difficult tasks. Recently, we improved the laser absorptivity of copper powder by nano-TiC modification, and fabricated a sample with a density of 99.8% under a 1064 nm laser (340 W, 500 mm/s). Our modification technique provides a novel solution to the above problem.

Methods The reflectivities of nano-TiC, unmodified pure copper powder, and copper powder modified with 0.2%(mass fraction) nano-TiC were measured under lasers of different wavelengths. Measurements were performed in a UV-3600 plus ultraviolet spectrophotometer. The morphologies of the powders and nano-TiC particles were observed by scanning electron microscopy with energy-dispersive X-ray spectroscopy. The unmodified and modified copper powders were subjected to selective laser melting in a metal 3D printer (EOS M290) operated with a 400 W and 1064 nm laser under the same scanning conditions (340 W, 500 mm/s). The relative densities of the samples were determined by the Archimedes method. Their morphologies and hardness values were analyzed by a Nikon optical microscope and a Brinell hardness tester, respectively. The thermal and electrical conductivities of the samples were measured by a laser thermal conductivity meter and a Hall effect tester, respectively.

Results and Discussions The observation and analyses confirmed that: a) modifying the copper powder with 0.2% nano-TiC significantly reduced the reflectivity of copper to 1064 nm laser, and consequently increased the laser absorptivity from 22% to 53.7% (Fig. 4); b) the sample modified with the powder had a much higher relative density (99.8%) and significantly fewer defects than the sample fabricated from unmodified pure copper powder under the same conditions (340 W, 500 mm/s) (Fig. 5); c) modification with nano-TiC improved the Brinell hardness of the samples from 64.5 to 87.7 HB (Fig. 6); d) the modification improved the thermal and electrical conductivities of the samples from 120.8 W/(m·K) and 29.1% IACS, respectively, to 189.2 W/(m·K) and 42.1% IACS, respectively. The improved relative density fundamentally improved the performance of the samples.

Conclusions The proposed modification increased the relative density of copper powder from 90.7% to 99.8% and improved its laser absorptivity from 22% to 53.7% under a 1064 nm laser (340 W, 500 mm/s). The high relative density correspondingly improved the Brinell hardness, thermal conductivity, and electrical conductivity of the modified sample. Modification by nano-TiC is a novel and effective technique for increasing the laser absorptivity of copper and fabricating high-density copper parts by selective laser melting under low-power laser scanning.

黎振华, 申继标, 李淮阳, 滕宝仁, 刘静. 纳米TiC改性对选区激光熔化铜成形的影响[J]. 中国激光, 2021, 48(3): 0315001. Zhenhua Li, Jibiao Shen, Huaiyang Li, Baoren Teng, Jing Liu. Effect of Nano-TiC Modification on Selective Laser Melting of Copper[J]. Chinese Journal of Lasers, 2021, 48(3): 0315001.

本文已被 1 篇论文引用
被引统计数据来源于中国光学期刊网
引用该论文: TXT   |   EndNote

相关论文

加载中...

关于本站 Cookie 的使用提示

中国光学期刊网使用基于 cookie 的技术来更好地为您提供各项服务,点击此处了解我们的隐私策略。 如您需继续使用本网站,请您授权我们使用本地 cookie 来保存部分信息。
全站搜索
您最值得信赖的光电行业旗舰网络服务平台!