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引言根据美国材料试验学会(ASTM)平面应变断裂韧度K_(IC)的有效标准,测定的断裂韧度应满足下列条件:(i)试件几何尺寸应使“α”与“B”≥2.5(K_Q/σ_Y)~2;(ii)载荷-位移曲线应满足P_(max)<1.1P_Q。由于试验材料取自构件的各个部分,致使试件尺寸受到限制,常难以满足厚度的要求。首先,用不同尺寸的紧凑拉伸试件研究K_(IC)的有效标准。其次,用低压汽轮机大轴的材料制备345毫米厚、920毫米直径的大型圆盘试件进行试验,以评价其在最低使用温度(近于室温)下的断裂韧度。最后,还研究了该材料的回火脆化敏
INTRODUCTION Fracture toughness, as determined by the American Society for Testing and Materials (ASTM) effective fracture toughness, K_ (IC), shall meet the following conditions: (i) The specimen geometry shall be such that “α” and “B” (K_Q / σ_Y) ~ 2; (ii) The load-displacement curve should satisfy P_ (max) <1.1P_Q. Due to the test material taken from various parts of the component, resulting in specimen size is limited, often difficult to meet the thickness requirements. First, the effective test of K_ (IC) is studied with compact tensile specimens of different sizes. Next, a 345 mm thick, 920 mm diameter, large disc specimen was prepared from the material of the low pressure turbine shaft to assess its fracture toughness at the lowest possible service temperature (near room temperature). Finally, the temper embrittlement sensitization of this material was also studied