压铸模具钢热机械疲劳损伤机制研究
Research on Thermal Mechanical Fatigue Damage Mechanism of Internal Pressure Die Casting Steel
纪帅 1张红岩1
作者信息
- 1. 平顶山职业技术学院 机电工程系,平顶山 467000
- 折叠
摘要
热机械疲劳(Thermal Mechanical Fatigue,TMF)是压铸模具钢在高温和机械应力下的重要损伤形式.通过分析TMF加载条件下的疲劳断口特征,揭示其与传统低周疲劳不同的疲劳断口特征.研究发现:TMF的疲劳断口具有疲劳源区、裂纹扩展区和断裂区3个明显区域,其中裂纹扩展区面积最大;在不同加载条件下,断裂区的特征存在一定变化趋势.此外,在TMF过程中观察到断口表面的氧化现象在不同相位下呈现不同特征,这与加载条件及材料性质有关.研究还发现,在TMF过程中存在预缩现象,尤其在外部压力-热机械疲劳(External Pressure-Thermal Mechanical Fatigue,EP-TMF)条件下更为显著,这与低温半周塑性变形有关.
Abstract
Thermal mechanical fatigue(TMF)is an important damage form of die casting steel under high temperature and mechanical stress.By analyzing the fatigue fracture characteristics under TMF loading conditions,the fatigue fracture characteristics different from traditional low-cycle fatigue are revealed.The results show that the fatigue fracture of TMF has three obvious regions:fatigue source region,crack growth region and fracture region,in which the crack growth region is the largest.Under different loading conditions,the characteristics of the fracture zone have a certain variation trend.In addition,it is observed that the oxidation of the fracture surface showed different characteristics at different phases during TMF process,which was related to loading conditions and material properties.It is also found that the pre-shrinkage phenomenon exists in the TMF process,especially in the condition of External Pressure-Thermal Mechanical Fatigue(EP-TMF),which is related to the half-cycle plastic deformation at low temperature.
关键词
压铸模具/钢材/热机械疲劳(TMF)/损伤机制Key words
die casting mold/steel/Thermal Mechanical Fatigue(TMF)/damage mechanism引用本文复制引用
出版年
2024
NETL
NSTL
万方数据