【摘要】 以显微组织差异显著但抗拉强度相近的45CrNiMoVA钢和FGH96镍基高温合金为研究对象，采用电化学充氢法对45CrNiMoVA钢进行3～60 min的充氢处理，对FGH96合金进行48～96 h的充氢处理，采用在空气中静置的方法对充氢60 min的45CrNiMoVA钢进行24～144 h排氢处理，对充氢96 h的FGH96合金进行24～120 h的排氢处理，研究了氢对不同材料拉伸性能与断裂行为的影响。结果表明：充氢后45CrNiMoVA钢和FGH96合金的断后伸长率与抗拉强度均较未充氢状态显著降低，且随充氢时间延长，拉伸性能退化程度加剧，氢脆指数增大；FGH96合金性能退化程度显著低于45CrNiMoVA钢，氢脆指数也更低。充氢后45CrNiMoVA钢的裂纹萌生位置由充氢前的试样截面中心向外表面转移，萌生机制由塑性主导逐渐转变为脆性主导，裂纹萌生区与扩展区呈韧窝+准解理+沿晶裂纹混合特征；随充氢时间延长，准解理面积与沿晶裂纹密度显著增加。45CrNiMoVA钢的氢脆机制为氢增强局部塑性（HELP）与氢降低黏结性能机制（HEDE）的协同作用。未充氢和充氢FGH96合金.的裂纹均萌生于试样外表面，断口呈中心韧性断裂、边缘脆性断裂特征；随充氢时间延长，表面氢致裂纹增多，脆性区域形貌由准解理向解理转变，脆性区域深度增加。FGH96合金的氢脆机制主要为HELP机制，韧性断裂形貌未受氢的显著影响。随排氢时间延长，2种材料的断后伸长率和抗拉强度均逐渐恢复至接近未充氢状态，其氢致性能退化主要源于可逆的氢扩散行为。更多还原

【Abstract】 45CrNiMoVA steel and FGH96 nickel-based superalloy with significant microstructure differences but similar tensile strengths were used as the research objects. The 45 CrNiMoVA steel was subjected to electrochemical hydrogen charging for 3–60 min,and FGH96 alloy was subjected to electrochemical hydrogen charging for 48–96 h. The 45CrNiMoVA steel charged with hydrogen for 60 min and FGH96 alloy charged with hydrogen for 96 h were subjected to hydrogen outgassing for 24–144 h and 24–120 h,respectively,by standing in the air. The influence of hydrogen on the tensile properties and fracture behavior of different materials was studied. The results show that after hydrogen charging,the percentage elongation after fracture and tensile strength of 45CrNiMoVA steel and FGH96 alloy significantly decreased compared to those in the uncharged state. With the extension of hydrogen charging time,the degree of tensile property degradation was intensified,and the hydrogen embrittlement index increased. However,the degree of property degradation of FGH96 alloy was significantly lower than that of 45CrNiMoVA steel,and its hydrogen embrittlement index was also lower. After hydrogen charging,the crack initiation location of 45CrNiMoVA steel shifted from the center of the sample cross-section before hydrogen charging to the outer surface, the initiation mechanism gradually changed from plasticdominated to brittle-dominated,and the crack initiation zone and the propagation zone presented a mixed characteristic of indentations,quasi-cleavage and intergranular cracks;with the extension of hydrogen charging time,the quasi-cleavage area and intergranular crack density in these regions increased significantly. The hydrogen embrittlement mechanism of the 45CrNiMoVA steel was the synergistic effect of hydrogen enhancing local plasticity(HELP) and hydrogen reducing bonding performance(HEDE). Cracks in both uncharged and.hydrogen-charged FGH96 alloy were originated on the outer surface of the samples,and the fracture showed central ductile fracture and edge brittle fracture characteristics;with the extension of hydrogen charging time,the number of hydrogen-induced cracks on the surface increased,and the morphology of the brittle zone changed from quasi-cleavage to cleavage,with an increase in the depth of the brittle zone. The main hydrogen embrittlement mechanism of the FGH96 alloy was HELP mechanism,and the morphology of ductile fracture was not significantly affected by hydrogen. With the extension of hydrogen discharging time,the percentage elongation after fracture and tensile strength of the two materials were gradually returned to a state close to those under hydrogen-charging condition. The hydrogen-induced performance degradation mainly resulted from the reversible hydrogen diffusion behavior.更多还原