摘要
本文研究了δ-Ni_3Nb相的尺寸及分布对Inconel718合金在650℃,恒应变控制循环应变作用下断裂行为的影响。结果表明,由高温固溶及中间时效造成的δ相沿晶界的锯齿状分布,可以提高材料对裂纹沿晶扩展的抗力,使低周疲劳断口由标准工艺处理后的沿晶型转变为穿晶。但是,与形成锯齿晶界的工艺相伴随的,δ相在晶内沿孪晶界面及贯穿晶粒的粗大片状析出,降低材料对循环应变的适应能力,常常过早地在δ相与基体界面处形成微孔甚至界面分离,使材料疲劳寿命降低。
The effect of size and distribution of σ-Ni_3Nb phase on the fatigue
fracture behaviour of Inconel 718 under constant controlled cyclic strain at 650℃
has been studied. The serrated distribution or σ-plates along grain boundaries, form-
ed by high temperature solid solution and intermediate aging, may improve the re-
sistance to crack propagation along boundary, so as to change the low cycle fatigue
fracture from intergranular, undergone standard heat treatment, into transgranular.
However, the precipitation of coarse plate σ-phase along twin boundaries and through
grains, after treated on the schedule for forming the serrated boundary, may
reduce the adoptability to cyclic strain and may often form too early the microvo-
ids at interface between σ-phase and matrix and even disintegrate to shorten the fa-
tigue life of steel.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
1991年第1期A055-A060,共6页
Acta Metallurgica Sinica
关键词
高温合金
疲劳
断裂
δ-Ni3Nb相
δ-Ni_3Nb phase
fatigue life
intergranular fracture
transgranular fracture
