深冷处理对连续C_f/ZL301复合材料拉伸强度与残余应力的影响

Effect of cryogenic treatment on tensile strength and residual stress of continuous C_f/ZL301 composite

选用M40石墨纤维(6K)和ZL301铝合金作为增强体和基体,采用真空气压浸渗法制备了纤维体积分数40%的单向连续C_f/ZL301复合材料,研究冷处理及退火处理对连续C_f/ZL301复合材料的拉伸强度和残余应力的影响。结果表明:液氮深冷处理12、24和48 h后可以提高连续C_f/ZL301复合材料的拉伸强度,其中经液氮深冷处理12 h的复合材料强度提高幅度最大,较铸态提高13.5%;干冰冷处理对连续C_f/ZL301的拉伸强度影响不大;而退火处理使连续C_f/ZL301复合材料的强度下降18.6%。影响复合材料拉伸强度的原因应是不同的处理工艺产生的由体积收缩导致的孔隙闭合效应程度不一以及在不同程度上改变复合材料的残余应力。

The vacuum gas pressure infiltration was performed for the continuous C_f/ZL301 composite with the volume fraction of 40%, of which the reinforced material was M40 graphite fiber and the matrix alloy was ZL301 alloy, both the effects of cryogenic treatment and annealing treatment on the tensile strength and residual stress of continuous C_f/ZL301 composites were studied. The results show that the tensile strength of C_f/ZL301 composites can be improved after cryogenic treatment for 12 h, 24 h or 48 h in liquid nitrogen. The tensile strength of C_f/ZL301 composites has the largest improved after cryogenic treatment for 12 h in liquid nitrogen, compared with the as cast composite increased of 13.5%.Dry ice treatment has little effect on the tensile strength of C_f/ZL301. The tensile strength of C_f/ZL301 composites decreases of 18.6% by annealing treatment. The reason for effecting on the tensile strength of C_f/ZL301 composites should be that the pore closure is different caused by volume shrinkage and the residual stress of composite has changed in different extent because of the different treatment process.