窒化ケイ素セラミックスの繰返し荷重下におけるき裂進展挙動 : 荷重波形および圧縮荷重の影響

概要

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In order to know the influences of load wave form and compressive oads on the crack propagation behavior of sintered Si_3N_4 under cyclec loads, the crack propagation rate was measured using compact tension specimens at room temperature. The main results obtained are as follows. (1) The influences of stress ratio and test frequency to the crack propagation under sine wave form cyclic loads were equal to those under square wave form cyclic loads. (2) In the range of large ΔK_<Imax>, the crack propagated nearly time dependently. In the range of small ΔK_<Imax>, the crack propagated cycle dependently. (3) Crack closure phenomenon was observed using the unloading elastic compliance method. (4) The effective stress intensity factor range ΔK_<eff>, together with ΔK_<Imax>, can be a reasonable parameter to describe the crack propagation rate. (5) The compressive load crushed the debris, lowered the crack lpeniing load and resulted in a large ΔK_<eff> which promote the increase of the crack propagation rate.
社団法人日本材料学会の論文
1989-10-15