【摘要】 通过自制Coffin型及自约束型热疲劳试验机研究了5CrMnMc钢经不同热处理后的热疲劳行为。利用扫描电镜、透射电镜等揭示了热疲劳裂纹萌生及其扩展。结果表明,淬火态的5CrMnMo钢绝大多数热疲劳裂纹优先在晶界处萌生;淬回火态的试样裂纹主要萌生于碳化物与基体的脱开处,或形成晶界裂纹;无论是淬火或淬回火态的试样其热疲劳裂纹主要沿着碳化物与基体脱开处及晶界裂纹桥接而扩展。更多还原

【Abstract】 The thermal fatigue behaviour of 5CrMnMo steel after various heattreatments has been examined by means of Coffin-model and self-strained thermalfatigue testing machines, The thermal fatigue crack initiation and propagation havebeen observed under SEM and TEM. The majority of thermal fatigue crack was in-itiated through the grain boundaries for the quenched steel and through the breakof interface between carbide and matrix or crack of grain boundary for quenchedand tempered one. The thermal fatigue crack propagated mainly through the break-age of the interface of carbide and grain boundaries for either quenched or quen-ched and tempered steel.更多还原