LY12/Cu双金属层合板的疲劳性能(Ⅱ)——角裂纹

Fatigue crack propagation in LY12/Cu double-layer metal laminates(Ⅱ) ── Angle crack

对爆炸复合双层金属板LY12 /Cu和LY12 /LY12中L T取向角裂纹的疲劳扩展行为进行了对比性实验研究和理论分析。结果表明 ,双层金属板的界面相性能、体积分数及界面两侧材料的性能差异对层合板中角裂纹的疲劳扩展具有重要影响。对由不同金属构成的双层复合板 ,角裂纹疲劳扩展过程中试样两侧面的裂纹长度不同 ,并且随着裂纹扩展其差距逐渐加大 ,但存在最大值Δac。当两侧面裂纹长度差Δa <Δac 时 ,两侧裂纹扩展速率不同 ;当Δa≥Δac 时 ,两侧裂纹扩展速率相同。对整个裂纹扩展过程可用Δac 和其后任一侧的裂纹扩展ΔK—da/dN曲线共同描述。

The angle crack fatigue growth behavior in two kinds of explosive bonded double-layer metal composite plates (LY12/LY12, LY12/Cu) was investigated. The results indicate that the properties of the interface and the components have significant influence on the angle-crack fatigue growth. For double layer plates with different components, during the fatigue propagation, the crack lengths on two sides surface of the same specimen are not the same. Their difference Δa is increasing with the fatigue growing and has a maximum value Δa c. The fatigue crack growth rates of two sides of the same specimen are not the same if Δa<Δa c, and after Δa≥Δa c, the fatigue crack growth rates are the same. The suitable characterization of the angle crack fatigue propagation in double layer laminates should combine the Δa c with the curve of ΔK-da/dN of one side after Δa≥Δa c.