Mechanical performance of Zirconia-toughened alumina composites: the dual role of nitinol as a toughening and sintering aid

Mudzaffar, Raqibah Najwa and Mohd Ali, Afifah and Ibrahim Sktani, Zhwan Dilshad and Rejab, Nik Akmar and Mohd Zaki, Hafizah Hanim and Sarifuddin, Norshahida and Ahmad, Zuraida and Ahmad Azhar, Ahmad Zahirani and Abdullah, Norazharuddin Shah (2025) Mechanical performance of Zirconia-toughened alumina composites: the dual role of nitinol as a toughening and sintering aid. Jurnal Kejuruteraan, 37 (7). pp. 3471-3481. ISSN 0128-0198 E-ISSN 2289-7526

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Abstract

Zirconia-toughened alumina (ZTA) is an advanced ceramic material used in various applications, including cutting inserts, wear parts, and biomedical applications, due to its improved fracture toughness and suitable hardness. However, further improvement of mechanical properties is still a key consideration for expanding its applicability in such demanding applications. Hence, this study examines the effects of nitinol (NiTi) additions (0–5 wt %) on the physical and mechanical properties of ZTA composites. NiTi was incorporated through wet mixing and the samples were sintered at 1600°C, facilitating liquid-phase sintering at 1300°C. At 2 wt% NiTi, optimal densification (4.197 g/cm³), minimal porosity (0.135%), and maximum hardness (1684.15 HV) were achieved, primarily due to microstructural refinement and the Hall-Petch effect. At higher NiTi content (5 wt%), enhanced fracture toughness (5.966 MPa·m¹/²) was observed, resulting from crack-bridging and stress dissipation enabled by NiTi’s ductility and the presence of the retained B2 austenite phase. X-ray diffraction (XRD) analysis confirmed phase stability with no evidence of secondary phase formation. These findings highlight a trade-off between hardness and fracture toughness, demonstrating NiTi’s dual role as a sintering aid and toughening agent. The results offer significant potential for tailoring ZTA composites for advanced mechanical applications, particularly in the development of high-performance cutting tools and wear-resistant components.

Item Type:	Article (Journal)
Uncontrolled Keywords:	ZTA composites; Nitinol additive; liquid-phase sintering; fracture toughness; hardness
Subjects:	T Technology > T Technology (General) > T175 Industrial research. Research and development
Kulliyyahs/Centres/Divisions/Institutes (Can select more than one option. Press CONTROL button):	Kulliyyah of Engineering > Department of Manufacturing and Materials Engineering Kulliyyah of Engineering
Depositing User:	Dr. Afifah Mohd. Ali
Date Deposited:	05 Nov 2025 16:28
Last Modified:	05 Nov 2025 16:28
URI:	http://irep.iium.edu.my/id/eprint/124115

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