Microstructure and mechanical properties of Co-free maraging steel fabricated by double-wire CMT + P arc-directed energy deposition

IF 5.5 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Materials Characterization Pub Date : 2025-09-14 DOI:10.1016/j.matchar.2025.115564

Gaige Chang , Dongqing Yang , Pengfei Gao , Qiangkun Wang , Baihao Cai , Yong Huang , Heguo Zhu , Kehong Wang

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Abstract

A Co-free maraging steel component, demonstrating excellent forming quality and freedom from internal defects, was successfully fabricated using the double-wire CMT + P arc-directed energy deposition (DED-Arc) process at a deposition rate of 6.4 kg/h. The microstructural evolution and mechanical properties of the deposited component were examined. Results revealed the component possessed a multi-layer structure along the building direction. Horizontally, it exhibited an alternating structural pattern comprising overlap areas (OA) and central fusion zones (CFZ). The overall microstructure consists of martensite, austenite, and Ni₃Ti precipitates. Austenite content increased and grain size decreased towards the bottom, attributed to varying heat dissipation conditions and inherent thermal cycles during DED-Arc. Compared to the OA, the CFZ exhibited a finer grain size and a higher proportion of high-angle grain boundaries (HAGBs); however, no significant difference was observed in the distribution of Ni₃Ti precipitates between the two regions. Tensile strengths were measured at 1163 ± 32 MPa (X), 1183 ± 33 MPa (Y), and 1135 ± 11 MPa (Z). Corresponding impact toughness values were 34.5 ± 3.1 J/cm² (X), 34.3 ± 1.9 J/cm² (Y), and 37.8 ± 4.3 J/cm² (Z). Ductile fracture predominated in both tension and impact tests. Microhardness in the top region was relatively low due to heat accumulation and thermal history variations. Furthermore, microstructural differences between the OA and CFZ led to higher microhardness in the CFZ. These findings demonstrate the successful application of the double-wire CMT + P DED-Arc process for maraging steel, providing an important reference for the future development of efficient, high-performance DED-Arc processes.

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双线CMT + P电弧定向能沉积制备无co马氏体时效钢的组织和力学性能

采用双线CMT + P电弧定向能沉积（d - arc）工艺，以6.4 kg/h的沉积速率成功制备了一种无co马氏体时效钢构件，具有良好的成形质量和无内部缺陷。研究了沉积构件的显微组织演化和力学性能。结果表明，该构件沿建筑方向呈多层结构。在水平上，它呈现出重叠区（OA）和中心融合区（CFZ）交替的结构格局。总体组织由马氏体、奥氏体和Ni₃Ti相组成。由于电弧过程中不同的散热条件和固有的热循环，奥氏体含量向底部增加，晶粒尺寸向底部减小。与OA相比，CFZ的晶粒尺寸更细，高角晶界（HAGBs）比例更高；然而，在两个地区之间，Ni₃Ti沉淀的分布没有显著差异。抗拉强度分别为1163±32 MPa (X)、1183±33 MPa (Y)和1135±11 MPa (Z)。相应的冲击韧性值分别为34.5±3.1 J/cm2 (X)、34.3±1.9 J/cm2 (Y)和37.8±4.3 J/cm2 (Z)。韧性断裂在拉伸和冲击试验中均占主导地位。由于热积累和热历史的变化，顶部区域的显微硬度相对较低。此外，OA和CFZ的显微组织差异导致CFZ的显微硬度更高。这些研究结果表明双线CMT + P d -电弧工艺在马氏体时效钢中的成功应用，为今后开发高效、高性能的d -电弧工艺提供了重要参考。

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来源期刊

Materials Characterization 工程技术-材料科学：表征与测试

CiteScore

7.60

自引率

8.50%

发文量

746

审稿时长

36 days

期刊介绍： Materials Characterization features original articles and state-of-the-art reviews on theoretical and practical aspects of the structure and behaviour of materials. The Journal focuses on all characterization techniques, including all forms of microscopy (light, electron, acoustic, etc.,) and analysis (especially microanalysis and surface analytical techniques). Developments in both this wide range of techniques and their application to the quantification of the microstructure of materials are essential facets of the Journal. The Journal provides the Materials Scientist/Engineer with up-to-date information on many types of materials with an underlying theme of explaining the behavior of materials using novel approaches. Materials covered by the journal include: Metals & Alloys Ceramics Nanomaterials Biomedical materials Optical materials Composites Natural Materials.