Visualization of microstructural factors resisting the crack propagation in mesosegregated high-strength low-alloy steel
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2020年第7期
论文作者：Shuxia Wang Chuanwei Li Lizhan Han Haozhang Zhong Jianfeng Gu
文章页码：75 - 84
摘 要：While relationship between fracture mechanism and homogeneous microstructures has been fully understood,relationship between fracture mechanism and inhomogeneous microstructures such as the mesosegregation receives less attention as it deserves.Fracture mechanism of the high-strength low-alloy（HSLA） steel considering the mesosegregation was investigated and its corre s ponding micro structure was characterized in this paper.Mesosegregation re fers to the inhomogeneous distribution of alloy elements during casting solidification,and leads to the formation of positive segregation zones（PSZ） and negative segregation zones（NSZ） in ingots.The fracture surface of impact sample exhibits the quasi-cleavage fracture at-21 ℃,and is divided into ductile and brittle fracture zone.Meanwhile,the PSZ and NSZ spread across ductile and brittle fracture zone randomly.In ductile fracture zone,micro-voids fracture mechanism covers the PSZ and NSZ,and higher deformation degree is shown in the PSZ.In brittle fracture zone,secondary cleavage cracks are observed in both PSZ and NSZ,but present bigger size and higher quantity in the NSZ.However,some regions of the PSZ still present micro-voids fracture mechanism in brittle fracture zone.It reveals that the microstructures in the PSZ exhibit a higher resistance ability to crack propagation than that in the NSZ.All observations above provide a better visualization of the microstructural factors that resist the crack propagation.It is important to map all information regarding the fracture mechanism and mesosegregation to allow for further acceptance and industrial use.
Shuxia Wang1，Chuanwei Li1，Lizhan Han2，Haozhang Zhong1，Jianfeng Gu3,4
1. Institute of Materials Modification and Modeling, School of Materials Science and Engineering, Shanghai Jiao Tong University2. Shanghai Key Laboratory of Materials Laser Processing and Modification, Shanghai Jiao Tong University3. Collaborative Innovation Center for Advanced Ship and Deep Sea Exploration, Shanghai Jiao Tong University4. Materials Genome Initiative Center, Shanghai Jiao Tong University
摘 要：While relationship between fracture mechanism and homogeneous microstructures has been fully understood,relationship between fracture mechanism and inhomogeneous microstructures such as the mesosegregation receives less attention as it deserves.Fracture mechanism of the high-strength low-alloy（HSLA） steel considering the mesosegregation was investigated and its corre s ponding micro structure was characterized in this paper.Mesosegregation re fers to the inhomogeneous distribution of alloy elements during casting solidification,and leads to the formation of positive segregation zones（PSZ） and negative segregation zones（NSZ） in ingots.The fracture surface of impact sample exhibits the quasi-cleavage fracture at-21 ℃,and is divided into ductile and brittle fracture zone.Meanwhile,the PSZ and NSZ spread across ductile and brittle fracture zone randomly.In ductile fracture zone,micro-voids fracture mechanism covers the PSZ and NSZ,and higher deformation degree is shown in the PSZ.In brittle fracture zone,secondary cleavage cracks are observed in both PSZ and NSZ,but present bigger size and higher quantity in the NSZ.However,some regions of the PSZ still present micro-voids fracture mechanism in brittle fracture zone.It reveals that the microstructures in the PSZ exhibit a higher resistance ability to crack propagation than that in the NSZ.All observations above provide a better visualization of the microstructural factors that resist the crack propagation.It is important to map all information regarding the fracture mechanism and mesosegregation to allow for further acceptance and industrial use.
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