通过实现超细微观结构提高激光增材制造Ti6Al4V合金的硬度和耐磨性能。

Enhancing Hardness and Wear Performance of Laser Additive Manufactured Ti6Al4V Alloy Through Achieving Ultrafine Microstructure.

作者信息

Li Yanqin, Song Lijun, Xie Pan, Cheng Manping, Xiao Hui

机构信息

State Key Laboratory of Advanced Design and Manufacturing for Vehicle Bodies, Hunan University, Changsha 410082, China.

Hunan Provincial Key Laboratory of Intelligent Laser Manufacturing, Hunan University, Changsha 410082, China.

出版信息

Materials (Basel). 2020 Mar 8;13(5):1210. doi: 10.3390/ma13051210.

DOI:10.3390/ma13051210

PMID:32182664

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC7085053/

Abstract

Refining microstructure is an important issue for laser additive manufacturing (LAM) of titanium alloy. In the present work, the microstructures of LAM-fabricated Ti6Al4V alloy were refined using a low energy density with the combination of a small spot diameter, a low laser power, and a high scanning speed. The microstructure, hardness, wear performance, and molten pool thermal behavior of LAM-fabricated Ti6Al4V coatings were studied. The results show that the grain sizes of both prior β and α phases are strongly dependent on the cooling rate of the molten pool. The fine prior β grains and submicron-scale acicular α phases were obtained under a low energy density of 75 J mm due to the high cooling rate of the molten pool. In addition, the as-fabricated Ti6Al4V sample with submicron-scale acicular α phase showed a very high hardness of 7.43 GPa, a high elastic modulus of 133.6 GPa, and a low coefficient of friction of 0.48. This work provides a good method for improving the microstructure and mechanical performance of LAM-fabricated Ti6Al4V alloy.

摘要

细化微观结构是钛合金激光增材制造（LAM）的一个重要问题。在本工作中，通过结合小光斑直径、低激光功率和高扫描速度的低能量密度来细化激光增材制造的Ti6Al4V合金的微观结构。研究了激光增材制造的Ti6Al4V涂层的微观结构、硬度、磨损性能和熔池热行为。结果表明，原始β相和α相的晶粒尺寸都强烈依赖于熔池的冷却速率。由于熔池的高冷却速率，在75 J/mm的低能量密度下获得了细小的原始β晶粒和亚微米级针状α相。此外，具有亚微米级针状α相的增材制造Ti6Al4V样品显示出7.43 GPa的非常高的硬度、133.6 GPa的高弹性模量和0.48的低摩擦系数。这项工作为改善激光增材制造Ti6Al4V合金的微观结构和力学性能提供了一种好方法。