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带有局部圆形止焊区的钛合金扩散连接层合板能够改善层合板在拉-拉疲劳载荷作用下的裂纹扩展性能,为了研究止焊区尺寸对裂纹扩展寿命的影响,采用3mm,2mm,3mm厚钛合金板材通过扩散连接成8mm厚层合板,层合前预留12mm,15mm止焊区,并加工成含中心6mm孔的板状试件,进行了两类试件在含标识载荷的等幅载荷下的疲劳试验。通过断口判读裂纹形态和尺寸,得到裂纹扩展(a,N)数据,建立了裂纹扩展da/dN-a曲线,对裂纹扩展行为进行了对比。结果表明,裂纹扩展可分为3个阶段;止焊区尺寸对止焊区内裂纹扩展行为无明显影响,但随着止焊区尺寸的增加,止焊区边界附近和越过边界后的裂纹扩展速率有减缓趋势。
In order to study the effect of the size of the stop zone on the crack propagation life, a titanium alloy diffusion bonded laminate with a partial circular stop zone can improve the crack propagation performance of the laminate under the pull-pull fatigue loading. The 3mm, 2mm, 3mm thick titanium alloy sheet by diffusion into a 8mm thick laminate, laminated before leaving 12mm, 15mm stop zone, and processed into a center 6mm hole plate-like specimens were tested in two types of specimens Fatigue test under equal amplitude load for marking load. Crack propagation (a, N) data were obtained through the fracture interpretation of crack shape and size. Crack propagation da / dN-a curves were established and the crack propagation behavior was compared. The results show that the crack propagation can be divided into three stages. The size of the welding zone has no significant effect on the crack propagation in the welding zone. However, with the increase of the size of the welding zone, the crack propagation near the welding zone and beyond the boundary Rate has slowed down.