TA2,Q345及其爆炸复合板高周疲劳性能研究

Researches on High Cycle Fatigue Properties of TA2,Q345 and Their Explosively Bonded Plates

室温下,对覆板TA2、基板Q345、爆炸复合板TA2/Q345的光滑试样进行静态拉伸和高周疲劳试验;线性拟合出最大应力幅σmax和疲劳寿命N的关系曲线,并对其疲劳断口进行扫描分析。结果表明,复合板TA2/Q345的抗拉强度优于基板和覆板,疲劳强度介于基板与覆板之间,σ-1p=0. 31σb,复合板的疲劳比较小,抵抗疲劳作用的能力较差。复合板TA2/Q345疲劳断口呈现多源性,裂纹萌生于基板Q345表面,终断于覆板TA2;多源裂纹扩展交汇时形成台阶,基板Q345向覆板TA2扩展时出现了"爬坡"现象,且覆板TA2侧出现了"剥离撕裂"。由于覆板和基板弹性模量、晶体结构、金相组织的差异,造成复合板结合界面开裂。

At room temperature,static tensile and high cycle fatigue tests were carried out on the smooth specimens of TA2 clad plate,Q345 substrate and TA2/Q345 explosively bonded plate. The relation curve of maximum stress amplitude σmaxand fatigue life N was obtained by linear fitting,and scanning analysis was made on their fatigue fractures. The results show that the tensile strength of TA2/Q345 clad plate was better than that of the substrate and the explosively bonded plate,and its fatigue strength was between that of the substrate and that of the clad plate,σ-1 p= 0. 31σb,the clad plate had little fatigue and poor resistance to fatigue. The fatigue fracture of the TA2/Q345 clad plate was multi-source. The crack originated on the surface of Q345 substrate and finally broke on the TA2 clad plate. When the multi-source cracks grew and intersected,a step was formed. When the Q345 substrate propagated to TA2 clad plate,the phenomenon of"climbing"appeared,and the"stripping tear"appeared on the side of TA2 clad plate. The bonding interface crack was caused by the differences of the clad plate and the substrate in elastic modulus,crystal structure and metallographic structure.