外场辅助定向能量沉积钛合金研究进展

Research progress on directed energy deposited titanium alloy with auxiliary field

钛合金具有高强度、低密度与高断裂韧性等优异性能,已经广泛应用于航空航天、汽车工程与生物医学等领域。传统钛合金零件制造方法是通过铸造及后续机械加工的方式来获得最终产品,但传统方法难以加工结构复杂的钛合金零件,造成了材料的大量浪费。定向能量沉积为制造钛合金零件提供了一种更有效的加工路径,但该工艺仍然存在着若干问题,如粗大柱状晶、各种缺陷以及力学性能各向异性等。为改善上述问题,外场辅助被引入钛合金的定向能量沉积工艺中。本文主要介绍当前几种主流的外场(形变场、声场、磁场),总结和评述了外场辅助对定向能量沉积钛合金微观组织和力学性能的影响,并对外场辅助定向能量沉积钛合金的发展趋势进行展望。

Titanium alloys have been widely used in many fields such as aerospace,automobile biomedical due to their high strength,low density and high fracture toughness.Previously,the final shape and size of titanium parts are determined by conventional procedure,including forging/casting and subsequent machining,but it is difficult to fabricate titanium alloy parts with a complex shape,which results in a large amount of material waste.Direct energy deposition(DED)has provided an efficient way for preparing titanium alloy parts,but there are also some critical issues to be solved,such as coarse columnar grains,defects and the resulting anisotropy of mechanical properties.In order to solve the above problems,the auxiliary fields are introduced into the processing of direct energy deposition.This paper first provided a brief introduction to several auxiliary fields,such as deformation field,acoustic field,magnetic field,then the effects of auxiliary fields on the microstructure and mechanical properties of directed energy deposited titanium alloys were summarized and reviewed.Finally,the development trends of titanium alloys manufactured by directed energy deposition with an auxiliary field were proposed.