增强体形态、分布对铝基复合材料力学循环特性的影响研究

制备了4种不同增强形式的铝基复合材料:SiCp均匀增强(A)、SiCp集中增强(B)、Si3N4网络骨架增强(C)以及碳纤维三维编织增强(D),研究了它们在各种循环应力幅度和循环次数下的力学响应规律以及预力学循环对常规力学循环性能的影响.研究表明,在力学循环过程中,材料A、B、C均存在循环硬化,并都在最初10次循环内达到稳定;存在一个特定的预加载应力幅σm8,能使材料的屈服强度达到最理想;作为非连续增强体SiCp增强材料A,其T6时效态的屈服强度明显优于其他材料;连续增强体Si3N4网络陶瓷增强材料C强度较高而塑性不足;SiCp集中增强材料B兼具了非连续增强体和连续增强体的塑性和韧性;碳纤维增强材料D由于内部碳纤维混乱排布导致在力学循环过程中产生了循环软化.

Effects of Reinforcement Shape and Distribution on Mechanical Cycle Performance in Al Composites

Mechanical cycle performance of 6061Al composites reinforced by (A) uniform distributed SiCp,(B) centralize distributed SiCp, (C) Si3 N4 net reinforcement and (D) carbon fibre reinforcement are investigated experimentally. The results indicate that A, B and C have cyclic hardening, and all reach the steady state; The Si3 N4 net reinforced composite C has rapid increase of strength, but has bad plastic nature; The centralize reinforced composite B has both the good plastic nature and toughness; The carbon fibre reinforced composite D shows cyclic softening in mechanical cycle,it's probable because of the chaos distribution of carbon fibre.