摘要
导出了使裂纹脆性扩展的外加应力场强度因子K_I和断口分形维数D_F的关系式其中d_f是断裂单元尺寸,L_o是常数,γ是真实表面能,E’=E或E/(1-v^2)测出1nk_1-D_F直线就可获得真实表面能γ、此方程适用于过载断裂和滞后断裂(如氢致开裂和应力腐蚀) 实验表明,Ti—24Al—HNb在动态充氢时能发生氢致滞后断裂,且门槛值较低,K_(IH)/K_(IC)=0.43实验测出的K_(IC)
The relation between the Stress intensity factor K_I~* required for brittle crack
initiation and propagation and the fractal dimension D_F of the fracture surface was derived,
l.e.
lnK_I~* =(1/2)ln2γE'+(1/2)ln(d_f/L_0)·(1-D_F)
where d_f is the fracture unit, L_0 a material constant, γ the real surface energy and
E=E/(1-v^2). The surface energy can be calculated from the measured linear relation of the
lnK_I vs D_F The equation is not only suitable for the overloaded cracking but also for the de-
layed cracking (e.g. hydrogen induced cracking and stress corrosion cracking). The experi-
mental results showed that the hydrogen induced delayed cracking occurred in
Ti-24Al-11Nb during charging, and the threshold stress intensity value was low i.e.
K_(IH)/K_(IC)= 0.43. The relation between the stress intensity factor K_I~* and D_F measured by ex-
periment was consistent with the theoretical equation.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
1993年第9期A393-A399,共7页
Acta Metallurgica Sinica
基金
国家自然科学基金
关键词
钛基合金
氢致裂纹
断口
研究
Ti-24Al-11Nb
hydrogen induced cracking
fractal dimension
