Influence of laser surface remelting on microstructure and degradation mechanism in simulated body fluid of Zn-0.5Zr alloy
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2019年第11期
论文作者：Zheng Wang Qingke Zhang Robabeh Bagheri Pushan Guo Yirong Yao Lijing Yang Zhenlun Song
文章页码：2705 - 2713
摘 要：In this study,the Zn-0.5 wt%Zr（Zn-Zr） alloy was treated by laser surface remelting（LSR）,and then the microstructure and degradation mechanism of the remelting layer were investigated and compared with the original as-cast alloy.The results reveal that after LSR,the bulky Zn22Zr phase in the original Zn-Zr alloy is dissolved and the coarse equiaxed grains transform into fine dendrites with a secondary dendrite arm space of about 100 nm.During the degradation process in simulated body fluid（SBF）,the corrosion products usually concentrate at some certain areas in the original alloy,while the corrosion products distribute uniformly and loosely in the LSR-treated surface.After removing the corrosion products,it was found that the former suffers obvious pitting corrosion and then localized corrosion.The proposed mechanism is that corrosion initiates at grain boundaries and develops into the depth at some locations,and then leads to localized corrosion.For the LSR-treated sample,corrosion initiates at some active sites and propagates in all directions,corrosion takes place in the whole surface with distinctly uniform thickness reduction,while the localized corrosion and peeling of bulky Zn22Zr particles were eliminated.The electrochemical results also suggest the uniform corrosion of LSR-treated sample and localized corrosion of original sample.Based on the results,a new approach to regulate the corrosion mode of the biodegradable Zn alloy is proposed.
Zheng Wang1,2，Qingke Zhang1，Robabeh Bagheri1，Pushan Guo1，Yirong Yao1，Lijing Yang1，Zhenlun Song1
1. Key Laboratory of Marine Materials and Related Technologies,Zhejiang Key Laboratory of Marine Materials and Protective Technologies,Ningbo Institute of Materials Technology and Engineering,Chinese Academy of Sciences2. Nano Science and Technology Institute,University of Science and Technology of China
摘 要：In this study,the Zn-0.5 wt%Zr（Zn-Zr） alloy was treated by laser surface remelting（LSR）,and then the microstructure and degradation mechanism of the remelting layer were investigated and compared with the original as-cast alloy.The results reveal that after LSR,the bulky Zn22Zr phase in the original Zn-Zr alloy is dissolved and the coarse equiaxed grains transform into fine dendrites with a secondary dendrite arm space of about 100 nm.During the degradation process in simulated body fluid（SBF）,the corrosion products usually concentrate at some certain areas in the original alloy,while the corrosion products distribute uniformly and loosely in the LSR-treated surface.After removing the corrosion products,it was found that the former suffers obvious pitting corrosion and then localized corrosion.The proposed mechanism is that corrosion initiates at grain boundaries and develops into the depth at some locations,and then leads to localized corrosion.For the LSR-treated sample,corrosion initiates at some active sites and propagates in all directions,corrosion takes place in the whole surface with distinctly uniform thickness reduction,while the localized corrosion and peeling of bulky Zn22Zr particles were eliminated.The electrochemical results also suggest the uniform corrosion of LSR-treated sample and localized corrosion of original sample.Based on the results,a new approach to regulate the corrosion mode of the biodegradable Zn alloy is proposed.
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