Cu-0.54Al_2O_3弥散强化铜合金的拉伸变形和断裂行为  

TENSILE DEFORMATION AND FRACTURE BEHAVIOR OF Cu-0.54Al_2O_3 DISPERSION STRENGTHENED COPPER ALLOY

作　　者：程建奕[1] 汪明朴[1] 李周[1] 

机构地区：[1]中南大学材料科学与工程学院,长沙410083

出　　处：《复合材料学报》2004年第3期157-161,共5页Acta Materiae Compositae Sinica

基　　金：国家"863"高技术研究发展计划基金资助项目(2002AA302505)

摘　　要：　对Cu-0.54%Al2O3弥散强化复合材料的拉伸变形和断裂行为进行了研究。结果表明,经挤压比为30∶1的热挤压后,复合材料的σb、σ0.2、δ和σ0.2/σb分别高达340MPa、250MPa、24%和74%。冷加工后合金的强度随退火温度的升高而逐渐下降,但σ0.2/σb仍保持较高的值。挤压态合金的加工硬化指数n为0.256,明显低于纯铜。铜基体中均匀弥散分布着平均尺寸为18nm,间距为100nm的Al2O3纳米粒子,提高了铜基体的强度,阻碍了高温退火时再结晶的发生,降低了合金的加工硬化速率。挤压态合金的拉伸断口宏观上为杯锥状,微观上表现为明显的韧性断裂特征。The tensile deformation and fracture behavior of Cu-0.54%Al_2O_3 dispersion strengthened copper alloy were examined. The results show that σ_(0.2), σ_b, δ and σ_(0.2)/σ_b of Cu-0.54%Al_2O_3 composite reach 250 MPa, (340 MPa,) 24% and 74% respectively after hot-extruded in the extrusion ratio of 30∶1. The strength decreases gradually with the increase of annealing temperature, while σ_(0.2)/σ_b remains high value. Its strain hardening exponent n is 0.256, which is obviously lower than that of pure copper.The Al_2O_3 nanoparticles with the average size of 18 nm and mean interparticle spacing of 100 nm distribute uniformly in the copper matrix,and improve the strength of the copper matrix and prevent the matrix from recrystallizing during annealing at elevated temperature and lower the strain hardening exponent n. The fracture of the as-extruded composite on a macroscopic scale is cup and cone morphology and features with the toughness failure on the microscopic scale.

关 键 词：Cu—Al2O3 弥散强化 拉伸变形 断裂 加工硬化 

分 类 号：TB331[一般工业技术—材料科学与工程]