Through investigating the tension-tension fatigue behavior of an as-extruded Mg-6.2 wt.%Zn-0.6 wt.%Zr(ZK60)alloy,it revealed that the determined fatigue strength at 107 cycles was quite sensitive to the grain structur...Through investigating the tension-tension fatigue behavior of an as-extruded Mg-6.2 wt.%Zn-0.6 wt.%Zr(ZK60)alloy,it revealed that the determined fatigue strength at 107 cycles was quite sensitive to the grain structure.Among them,the fine grain structure had the highest fatigue strength of 130 MPa,whereas the typical“bi-modal”grain structure had the lowest fatigue strength of 110 MPa.Failure analysis demon-strated that for the fine grain structure,fatigue cracks preferentially nucleated at grain boundaries.For the“bi-modal”and coarse grain structures,the fatigue crack initiation was dominated by the cracking along slip bands.展开更多
In the present study,WB 2(N) films are fabricated on silicon and YG8 substrates at different N 2 pressures by reactive magnetron sputtering.The influence of N 2 partial pressure(P (N2)) on the film microstructur...In the present study,WB 2(N) films are fabricated on silicon and YG8 substrates at different N 2 pressures by reactive magnetron sputtering.The influence of N 2 partial pressure(P (N2)) on the film microstructure and characteristics is studied systematically,including the chemical composition,crystalline structure,residual stress,surface roughness as well as the surface and the cross-section morphology.Meanwhile,nano-indentation and ball-on-disk tribometer are performed to analyze the mechanical and tribological properties of the films.The results show that the addition of nitrogen apparently leads to the change of the structure from(1 0 1) to(0 0 1) orientation then to the amorphous structure with the formation of BN phase.And the addition of nitrogen can greatly refine the grain size and microstructure of the films.Furthermore,the residual stress of the film is also found to change from tensile to compressive stress as a function of P (N2),and the compressive stress increases with P (N2),The WB 2(N) films with small nitrogen content,which are deposited at P (N2) of 0.004 and 0.006 Pa,exhibit better mechanical,tribological and corrosion properties than those of other films.Further increase of nitrogen content accelerates the formation of BN phase and fast decreases the film hardness.In addition,the large N 2 partial pressure gives rise to the target poisoning accompanied by the increase of the target voltage and the decrease of the deposition rate.展开更多
基金financially supported by the National Natural Science Foundation of China Projects(Nos.51871211,U21A2049,52071220,51701129 and51971054)theLiaoningProvince’sProject of“Revitalizing Liaoning Talents”(No.XLYC1907062)+7 种基金the Doctor Startup Fund of Natural Science Foundation Program of Liaon-ing Province(No.2019-BS-200)the High Level Achievement Con-struction Project of Shenyang Ligong University(SYLUXM202105)the Strategic New Industry Development Special Foundation of Shenzhen(No.JCYJ20170306141749970)the funds of International Joint Laboratory for Light Alloys,Liaoning BaiQianWan Talents Pro-gram,the Domain Foundation of Equipment Advance Research of 13th Five-year Plan(No.61409220118)the National Key Re-search and Development Program of China(Nos.2017YFB0702001 and 2016YFB0301105)the Innovation Fund of the Institute of Metal Research(IMR),Chinese Academy of Sciences(CAS),the Na-tional Basic Research Program of China(973 Program)project(No.2013CB632205)the Fundamental Research Fund for the Central Universities(No.N2009006)the Bintech-IMR R&D Program(No.GYY-JSBU-2022-009).
文摘Through investigating the tension-tension fatigue behavior of an as-extruded Mg-6.2 wt.%Zn-0.6 wt.%Zr(ZK60)alloy,it revealed that the determined fatigue strength at 107 cycles was quite sensitive to the grain structure.Among them,the fine grain structure had the highest fatigue strength of 130 MPa,whereas the typical“bi-modal”grain structure had the lowest fatigue strength of 110 MPa.Failure analysis demon-strated that for the fine grain structure,fatigue cracks preferentially nucleated at grain boundaries.For the“bi-modal”and coarse grain structures,the fatigue crack initiation was dominated by the cracking along slip bands.
基金supported by the National Key Basic Research Program of China (973 Program,No.2012CB625100)the Natural Science Foundation of Liaoning Province of China (No.2013020093)
文摘In the present study,WB 2(N) films are fabricated on silicon and YG8 substrates at different N 2 pressures by reactive magnetron sputtering.The influence of N 2 partial pressure(P (N2)) on the film microstructure and characteristics is studied systematically,including the chemical composition,crystalline structure,residual stress,surface roughness as well as the surface and the cross-section morphology.Meanwhile,nano-indentation and ball-on-disk tribometer are performed to analyze the mechanical and tribological properties of the films.The results show that the addition of nitrogen apparently leads to the change of the structure from(1 0 1) to(0 0 1) orientation then to the amorphous structure with the formation of BN phase.And the addition of nitrogen can greatly refine the grain size and microstructure of the films.Furthermore,the residual stress of the film is also found to change from tensile to compressive stress as a function of P (N2),and the compressive stress increases with P (N2),The WB 2(N) films with small nitrogen content,which are deposited at P (N2) of 0.004 and 0.006 Pa,exhibit better mechanical,tribological and corrosion properties than those of other films.Further increase of nitrogen content accelerates the formation of BN phase and fast decreases the film hardness.In addition,the large N 2 partial pressure gives rise to the target poisoning accompanied by the increase of the target voltage and the decrease of the deposition rate.