Cyclic deformation behaviour of different crystallo- graphic orientation Al single crystals
摘要
Low lycle fatigue tests were carried out for Al single crystals. The results indicate: (i) At initial stage of fatigue life, peak stress a, ultrasonic attenuation Δα, friction stress σf, back stress σb and energy loss ΔE increase with increasing cycles. These parameters slowly change or do not change basically with cycles in cyclic saturation, (ii) The effect of single crystal orientations is evident. σ, Δα and σb of mono-slip crystals are smaller than that of double- and multi-slip crystals and Q-1 of the former is larger than that of the two latters. Their hysteresis loop shapes exhibit difference. (iii) Surface observation using SEM shows that the space of slip bands decreases in mono-, double- and multi-slip orientation crystals sequence.