Interfacial characterization and cracking behavior of NiTi/AlSi12 bimetallic structures fabricated by multi-material laser additive manufacturing

IF 4.8 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Materials Characterization Pub Date : 2025-04-23 DOI:10.1016/j.matchar.2025.115075

Zeng Zhang , Xiaojing Sun , Ding Yuan , Jiahua Wang , Haixin Li , Chao Wei

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引用次数: 0

Abstract

NiTi/AlSi12 bimetallic structures were fabricated by multi-material laser additive manufacturing (MM-LAM). The effects of different process parameters on the interface characteristics and microhardness of NiTi/AlSi12 bimetallic structures were studied. The interfacial layer thickness increases from 198.14 μm to 302.18 μm with the increase of laser energy density. A larger hatch space can alleviate the interfacial cracks. The larger hatch space can generate less continuous intermetallic compounds (IMCs), which leads to fewer cracks in the molten pool. Compared with the microhardness of NiTi and AlSi12 regions, the microhardness of the interface was the highest, with a maximum microhardness range of 650 HV–1000 HV. The interface composition, crack behavior, and crack formation mechanism of NiTi/AlSi12 bimetallic structures were analyzed. The interface mainly included the molten pool boundary region and the multiphase mixing region. In the interface, the molten pool boundary near the NiTi region was enriched with many nano-scale TiSi grains. The multiphase mixing region in the interface was mainly dominated by many TiAl, NiAl IMCs and a small amount of TiSi intermetallic silicides (IMSs). Cracks were initiated in the multiphase mixing region of the interface, where there were a large number of brittle IMCs and IMSs, with high residual stresses. The transgranular and intergranular propagation occurred along the multiphase mixing region, NiTi grains and grain boundaries in the interface. The crack is arrested in the multiphase mixing region rich in Al₃Ni₂. There was lower residual stress in this region. Moreover, it is calculated that Al₃Ni₂ had a low degree of anisotropy compared to other phases in the NiTi/AlSi12 interface, making it difficult to continue inducing micro-cracks. Therefore, the Al₃Ni₂-enriched region acts as a barrier to crack propagation.

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多材料激光增材制造制备NiTi/AlSi12双金属结构的界面表征及开裂行为

采用多材料激光增材制造技术（MM-LAM）制备了NiTi/AlSi12双金属结构。研究了不同工艺参数对NiTi/AlSi12双金属组织界面特性和显微硬度的影响。随着激光能量密度的增加，界面层厚度从198.14 μm增加到302.18 μm。较大的舱口空间可以缓解界面裂缝。较大的舱口空间可以减少连续金属间化合物（IMCs）的产生，从而减少熔池中的裂纹。与NiTi和AlSi12区的显微硬度相比，界面区的显微硬度最高，最大显微硬度范围为650 HV - 1000 HV。分析了NiTi/AlSi12双金属结构的界面组成、裂纹行为及裂纹形成机制。界面主要包括熔池边界区和多相混合区。在界面上，靠近NiTi区域的熔池边界富集了许多纳米尺度的TiSi晶粒。界面多相混合区主要由大量的TiAl、NiAl金属间硅化物和少量的TiSi金属间硅化物组成。界面多相混合区萌生裂纹，存在大量脆性IMCs和IMSs，残余应力较高。沿界面多相混合区、NiTi晶粒和晶界进行穿晶和沿晶扩展。裂纹止裂于富含Al3Ni2的多相混合区。该区域残余应力较低。此外，计算得出，与其他相相比，Al3Ni2在NiTi/AlSi12界面中具有较低的各向异性，难以继续诱导微裂纹。因此，富含al3ni2的区域是裂纹扩展的屏障。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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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.