Crack‐healing and mechanical behaviour of Al₂O₃/SiC composites at elevated temperature

Abstract

A B S T R A C T Alumina/silicon carbide (Al 2 O 3 /SiC) composite ceramics with large self-crack-healing ability, high strength and high heat-resistance limit temperature for strength were developed and subjected to three-point bending. A semicircular surface crack 100 µm in diameter was made on each sample. Crack-healing behaviour was systematically studied, as functions of crack-healing temperature and healing time, and the fatigue strengths of the crack-healed sample at room temperature and 1373 K were investigated. Four main conclusions were drawn from the present study.(1) Al 2 O 3 /SiC composite ceramics have the ability to heal after cracking from 1273to 1673 K in air.(2) The heat-resistance limit temperature for strength of the crack-healed sample is ∼ =1573 K, and ∼ =68% of the samples fractured from outside the crack-healed zone in the testing-temperature range 873-1573 K. (3) The crack-healed sample exhibited very high fatigue limit at room temperature and also 1373 K. (4) The large self-crack-healing ability is a desirable technique for the high structural integrity of ceramic component.

The effect of the TiC particle size on the preferred oxidation temperature for self-healing of oxide ceramic matrix materials

“…Of course, the required minimal temperature to trigger the healing reaction depends primarily on the chemical stability of the healing material in an oxygen-containing environment. This dependence has already been demonstrated (but apparently not been appreciated) in the combined first-generation studies on self-healing of Al 2 O 3 or Si 3 N 4 filled with SiC or Ni particles [3][4][5][6][7]. In these studies, the crack healing ability was studied as a function of both temperature (from 900 to 1400°C) and time (between 1 and 300 h) and widely different values were obtained for different particle sizes.…”

New Technology for Increasing Through-Life Reliability of Ceramics Components Using Self-Crack-Healing Ability

“…In contrast, in the case of process no. (10), is higher than csch , thus the materials are able to self-heal cracks introduced during service. Therefore, a higher level of reliability can be maintained by the self-crack-healing ability.…”

“…(a) SiC nanoparticles are added to the matrix, preventing grain growth in the matrix during the sintering process and improving its strength through grain refinement. For example, in the case of alumina, the bending strength can be increased from about 400 MPa to 700-1000 MPa by the inclusion of SiC nanoparticles [10]. (b) Composites containing 15-30 vol% nanosized SiC particles exhibit self-crack-healing ability.…”

“…Even in the case of ceramics, compressive residual stress is generated by localized plastic deformation or microcrack formation on the surface layer [7,8]. Considering the results obtained in previous Proof test (6) Service (7) Yes Service (10) If necessary lapping (3)…”

Effect of Self-Healing on Fatigue Behavior of Structural Ceramics and Influence Factors on Fatigue Strength of Healed Ceramics

“…The ceramic composites containing silicon carbide particles can heal surface cracks by themselves, as shown in Fig. 1 (Nakao et al, 2010, Ando et al, 2004. Surface cracking allows the silicon carbide particles on the crack walls to contact the oxygen in the surrounding atmosphere.…”