Cu－Ni－Al单晶的分形断裂与相变增韧

FRACTAL FRACTURE AND TRANSFORMATION TOUGHENING IN Cu-Ni-Al SINGLE CRYSTAL

测定了Ｃｕ－Ｎｉ－Ａｌ单晶在２０—１２０℃温度范围的断裂韧性ＫＣ和断裂表面的分形维数Ｄｆ．裂纹前沿应力诱导相变使母相有较高的ＫＣ．在单一断裂机制下，ｌｎＫＣ与Ｄｆ之间有简单的线性关系：脆性断裂时斜率为正，韧性断裂时斜率为负．由断裂微观机制与分形概念对上述结果进行分析讨论．

The fracture toughness KC and fractal dimension Df of fractured surfaces of Cu-Ni-Al single crystal have been measured at temperture range from 20℃to 120℃, in which thermoelastic martenstic transformation happened. The parent phase has higher KC than martensite phase due to stress induced transformation. The relationship between KC and Df has been studied especially and a linear relationship was found on semilog plot if failure mode is a simple mechanism. The slope of plot may be positive or negative for brittle or ductile failure respectively. The opposite relation can be understood by fracture micro-mechanism.