Effect of Sn Addition on Microstructure and Mechanical Properties of Sintered Ti2AlNb-Based Alloys

Li Zhu ¹

Yaran Zhang ²

Xifeng Yan ¹

Guoqing XIA ³

Qilin Yu ¹

Xinze Li ¹

Yongchang Liu ¹

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School of Materials Science and Engineering, Beijing institute of Technology, Beijing 100081, China |

Material Science Research Center, Xingtai University, Xingtai 054001, China |

Tianjin Key Laboratory of Integrated Design and On-line Monitoring for Light Industry & Food Machinery and Equipment, School of Mechanical Engineering, Tianjin University of Science and Technology, Tianjin 300457, China |

Publication type: Journal Article

Publication date: 2025-02-06

MDPI

Journal: Materials

scimago Q2

SJR: 0.565

CiteScore: 5.8

Impact factor: 3.1

ISSN: 19961944

DOI: 10.3390/ma18030715

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Abstract

Using cold isostatic pressing and atmospheric pressure sintering, Ti-18Al-28Nb-xSn alloys were synthesized by incorporating 0.5 at.%, 1 at.%, 2 at.%, and 4 at.% Sn powder into Ti, Al, and Nb powders. This study investigated the effects of Sn concentration on the microstructure and mechanical properties of Ti2AlNb-based alloys, with a particular focus on the underlying strengthening mechanisms. X-ray diffraction (XRD) analysis identified α2, O, and B2 as the primary phases in the alloy and demonstrated that Sn addition significantly influenced the proportions of these phases, thus impacting the overall mechanical performance of Ti2AlNb-based alloys. The optimal combination of elasticity, strength, and plasticity was achieved at a Sn concentration of 1 at.%; at this time, the elastic modulus of the alloy was 26.8 GPa, with a compressive strength of up to 1352 MPa and a fracture strain of 42.8%. However, further increases in Sn content beyond this level led to reductions in both strength and plasticity. At Sn concentrations above 2 at.%, increased porosity and the formation of micropores were observed, facilitating microcrack aggregation and fracture, which ultimately compromised the alloy’s mechanical integrity. By exploring the intrinsic strengthening mechanisms, this study tries to understand the influence of Sn on the strengthening effects and to optimize the content range of Sn addition to ensure the best strengthening effect and good density are shown in high-Nb-content TiAl alloy, providing a reference for future research in this field.