Bioinspired nacre-like 2024Al/B4C composites with high damage tolerance. Issue 18 (15th September 2022)

• Record Type: Journal Article
• Authors: Wang, Yang; Qiang Liu, ; Zhang, Biao; Zhang, Haoqian; Zhong, Zhaoxin; Ye, Jian; Ren, Yuhan; Shen, Liying; Ye, Feng; Wang, Wen
• Is Part Of: Ceramics international. Volume 48:Issue 18(2022)
• Page Start: 26326
• Page End: 26334
• Publication Date: 2022-09-15
• Subjects: B4C/Al composites -- Freeze casting -- Damage tolerance -- Pressure infiltration -- Bio-inspired; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2022.05.316
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: The bio-inspired 2024Al/B4 C composites with a laminate-reticular hierarchical architecture were constructed by squeeze casting of 2024Al into loose freeze-cast ceramic scaffolds. This pressurized infiltration process provided a clean and well-bonded interface without physical gaps. By regulating the initial suspension concentration (20, 25, 30 and 35 vol%), the effects of different ceramic content on the microstructure, damage-tolerance behavior and toughening mechanisms of the composites parallel and perpendicular to the ice-growth direction were investigated. The strength and toughness in the longitudinal direction were greater than that in the transverse direction. The 2024Al/20 vol% B4 C composite in the longitudinal direction yielded the highest flexural strength of 658 MPa, crack-initiation toughness ( K Ic ) of 18.4 MPa m 1/2 and crack-growth toughness ( K Jc ) of 27.5 MPa m 1/2 . The unique damage-tolerant properties were attributed to multiple toughening mechanisms, including crack deflection, branching and blunting, ductile-ligament bridging and multiple-crack propagation, as evidenced by the stable crack growth and rising R-curve behavior during fracture. The significantly decreased damage tolerance in the transverse direction was mainly due to inadequate toughening tools. On the other hand, both the flexural strength and fracture toughness reduced remarkably as the ceramic content increased. The 2024Al/35 vol% B4 C composite fractured in a single-crack mode and the crack growth path was almost straight, showing a relatively low flexural strength (502 MPa) and crack-initiation toughness (9.1 MPa m 1/2 ). The toughening mechanism was discussed in terms of the relationship between structural characteristics and cracking mode.