摘要
分别对裂纹尖端附近有塑性区和无塑性区的304不锈钢脉冲电流止裂试样进行了显微观察和纳米压痕试验。结果表明,有裂纹尖端塑性区的304不锈钢,在脉冲电流止裂后,止裂处发生了相变和再结晶,在温度场和应力场共同作用下分别形成了凝固区、细晶区和形变诱发马氏体区;而无裂纹尖端塑性区的304不锈钢,裂纹止裂处只有凝固区。纳米压痕试验表明304不锈钢的疲劳裂纹尖端处具有较大的残余应力,且残余应力随着远离裂纹尖端而迅速衰减;经过脉冲电流止裂后,裂纹尖端形变诱发马氏体的产生导致该处体积膨胀,产生相变应力,增大了裂纹止裂处周边的压应力值,这有利于抑制裂纹的二次扩展。
Microstructure observation and nano-indentation test were carried out on crack arresting specimens of 304 stainless steel with and without plastic zone near the crack tip.The results show that phase transformation and recrystallization are found to occur at the crack tip of 304 stainless steel with plastic zone after pulse current arrest,and the solidification zone,fine grain zone and deformation-induced martensite zone are formed under the co-action of the temperature field and the stress field.However,the solidification zone is only occurred in the specimen without the plastic zone.The nano-indentation test shows that the fatigue crack tip of 304 stainless steel has large residual stress,which decays rapidly with the increment of the distance from the crack tip.After pulse current crack arrest,the formation of deformationinduced martensite leads to the increase of both the volume expansion and the compressive stress around the arrest crack,which is beneficial to suppress the crack propagation.
作者
张朱武
潘光国
蒋艳
许承伟
Zhang Zhuwu;Pan Guangguo;Jiang Yan;Xu Chengwei(College of Chemical Engineering,Fuzhou University,Fuzhou Fujian 350116,China;Fujian Institute of Boiler and Pressure Vessel Inspection Research,Fuzhou Fujian 350008,China)
出处
《金属热处理》
CAS
CSCD
北大核心
2020年第7期130-134,共5页
Heat Treatment of Metals
基金
国家自然科学基金(51705077)
福建省自然科学基金(2018J01768)。
关键词
304不锈钢
塑性区
裂纹止裂
纳米压痕
形变诱发马氏体
304 stainless steel
plastic zone
crack arrest
nanoindentation
deformation-induced martensite
