The flattening test,using one pair paralleled plates to flatten tube structure radially,is generally employed to examine the ductility of tube used in once through steam generator(OTSG).This study focuses on the stres...The flattening test,using one pair paralleled plates to flatten tube structure radially,is generally employed to examine the ductility of tube used in once through steam generator(OTSG).This study focuses on the stress condition and deformation mechanism analysis on the concentrated stress regions of Ti-2 Al-2.5 Zr alloy tube during the flattening test.Firstly,the finite element analysis was performed using the commercial software ABAQUS to determine the stress condition.Secondly,the Electron BackScattered Diffraction(EBSD)was implemented to observe the microstructure evolution of Ti-2 Al-2.5 Zr alloy.Finally,Schmid law was employed to analyze the activated deformation mechanism under condition of the complex stress.It was found that the condition of the complex stress in stress concentration regions,including tension and compression regions,can be simplified into two directional stresses condition.In grains whose c-axis is nearly towards TD and ND,the strain is mainly accommodated by prismatic slip,whereas in grains whose c-axis deviates about 45°from ND to TD mainly by basal slip.The{10-12}extensive twin and corresponding parent grain orientation mainly relied on the stress condition.Additionally,the intergranular twin pairs connected at common grain boundaries(GBs)with high strain compatibility were found at low angle GBs,which were activated under a combination of macro stress and strain compatibility effect.展开更多
The fretting wear behavior of Zr alloy cladding tube under mixed fretting regime in a high-temperature pressurized water was investigated.The main wear mechanism is adhesive wear,with characters of small-scale delamin...The fretting wear behavior of Zr alloy cladding tube under mixed fretting regime in a high-temperature pressurized water was investigated.The main wear mechanism is adhesive wear,with characters of small-scale delamination at the center of worn area and serious delamination on the worn edge.A long crack throughout the worn area and other cracks propagated towards the substrate are observed.The cross-sectional microstructure of worn area can be divided into a thick third-body layer,thin inner oxide layer and thick tribologically transformed structure layer,and their formation mechanisms are analyzed in detail.Finally,the mixed fretting regime process and the microstructural evolution during fretting wear are discussed.展开更多
基金financial support from the National Natural Science Foundation of China(Nos.51875398 and 51471116)the Sichuan Science and Technology Program(2019ZDZX0001)+1 种基金the Project of Nuclear Power Technology Innovation Center of Science Technology and Industry for National Defense(HDLCXZX-2019-ZH-26)the Science and Technology on Reactor System Design Technology Laboratory,Nuclear Power Institute of China。
文摘The flattening test,using one pair paralleled plates to flatten tube structure radially,is generally employed to examine the ductility of tube used in once through steam generator(OTSG).This study focuses on the stress condition and deformation mechanism analysis on the concentrated stress regions of Ti-2 Al-2.5 Zr alloy tube during the flattening test.Firstly,the finite element analysis was performed using the commercial software ABAQUS to determine the stress condition.Secondly,the Electron BackScattered Diffraction(EBSD)was implemented to observe the microstructure evolution of Ti-2 Al-2.5 Zr alloy.Finally,Schmid law was employed to analyze the activated deformation mechanism under condition of the complex stress.It was found that the condition of the complex stress in stress concentration regions,including tension and compression regions,can be simplified into two directional stresses condition.In grains whose c-axis is nearly towards TD and ND,the strain is mainly accommodated by prismatic slip,whereas in grains whose c-axis deviates about 45°from ND to TD mainly by basal slip.The{10-12}extensive twin and corresponding parent grain orientation mainly relied on the stress condition.Additionally,the intergranular twin pairs connected at common grain boundaries(GBs)with high strain compatibility were found at low angle GBs,which were activated under a combination of macro stress and strain compatibility effect.
基金financially supported by the CNNC Science Fund for Talented Young Scholars,the Youth Innovation Promotion As-sessment CAS(No.2022187)the National Natural Science Founda-tion of China(No.52105221)+1 种基金the IMR Innovation Fund(No.2021-PY10)the open-ended fund of the CAS Key Laboratory of Nu-clear Materials and Safety Assessment(Institute of Metal Research,Chinese Academy of Sciences,China)(No.2020NMSAKF01).
文摘The fretting wear behavior of Zr alloy cladding tube under mixed fretting regime in a high-temperature pressurized water was investigated.The main wear mechanism is adhesive wear,with characters of small-scale delamination at the center of worn area and serious delamination on the worn edge.A long crack throughout the worn area and other cracks propagated towards the substrate are observed.The cross-sectional microstructure of worn area can be divided into a thick third-body layer,thin inner oxide layer and thick tribologically transformed structure layer,and their formation mechanisms are analyzed in detail.Finally,the mixed fretting regime process and the microstructural evolution during fretting wear are discussed.
