摘要
本文研究了在纯Al单晶样品的两个特殊面(包含动作Burgers矢量的S面和与Burgers矢量成最小夹角的T面)上由循环形变引起的裂纹启裂过程,疲劳试验结果表明,在循环形变过程中,S面上没有形成表面持续滑移带,但有很多微裂纹产生,裂纹较短,平均长度约为10μm,近似沿一个方向分布,与动作Burgers矢量垂直,而T面上裂纹的形貌大致与以前的工作相同。通过扫描超声显微镜观察,发现在S面上的疲劳损伤要比T面上的深得多,为此,作者提出了裂纹启裂的孔洞模型及持续滑移带形成模型。
An investigation was made of the crack initiation by cyclic deforma-
tion on the two special surfaces of pure Al single crystal. One is the tOp-surfaec
containing the active Burger's vector, and the other is the top-surface forming
the smallest angle with the active Burger's vector. The fatigue test were performed
at the constant resolved shear stress amplitude (5 Pa), zero mean stress. Expe-
rimentel results show that many microcracks are initiated on the side-surface on
which no PSB surface topographies are formed during cyclic deformation. Cracks on
the side-surface are short with mean length of about 10 μm and distributed appro-
ximately in a similar direction, perpendicular to the active Burger's vector, whereas
on the top-surface cracks are not as obvious as those on the side-surface. Observa-
tions by scanning acoustic microscopy show that the fatigue damage on the side-
surface is much deeper than that on the top-surface. A model of crack nucleation
by voiding, and of PSB formation is suggested.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
1991年第1期A023-A038,共16页
Acta Metallurgica Sinica
基金
国家自然科学基金资助课题
关键词
单晶体
铝
滑移带
疲劳损伤
裂纹
fatigue damage
single crystal
crack initiation
persistent slip band
acoustic microscope
