固体粒子の衝突によるSiCおよびSi₃N₄系セラミックスの破壊挙動

抄録

Ball contact damages were investigated on pressureless sintered SiC and Si₃N₄ ceramics. Impact tests were carried out using the air gun system. Three kinds of balls; steel, SiC and Si₃N₄, the size of which was 3mm in diameter, were used as projectiles, and four kinds of ceramics were used as target specimens of size 7.5×10×85mm. After the impact tests, three point bending tests were carried out to evaluate the residual strength of the specimens, and differences in failures with ball contact were discussed taking the results of numerical analyses into consideration.
The results are summarized as follows;
(1) The residual strength could not be estimated by the diameter of the ring crack.
(2) SiC specimens with steel ball impact, and Si₃N₄ specimens with SiC ball impact showed the largest degradation of strength.
(3) Distinction of fracture between SiC and Si₃N₄ specimens seemed to be caused by the differences in strength and fracture toughness of these materials.