The simultaneous improvement of strength and toughness in high-strength steels is a challenging task. Herein, a novel medium-carbon Ti−Mo-bearing martensite steel is developed. The influences of quenching temperature on microstructure evolution and strength−toughness are investigated. Microstructure and precipitation analyses are conducted to clarify possible reasons for the improvement of strength−toughness in the as-developed steel. After the addition of Ti and Mo, the martensite steel yields a high tensile strength of ≈1700 MPa and an impact energy of 43 J at –40 °C. The improved strength and toughness is attributed to better grain refinement strengthening and precipitation strengthening by combination of thermo−mechanical control process (TMCP) and quenching and tempering (Q−T) processes. Although no significant variation is observed in the strengths of Ti−Mo-bearing martensite steels quenched at a temperature range of 850−910 °C, the impact energy of Ti−Mo-bearing martensite steel obviously decreases at a higher quenching temperature of 910 °C. The decreased low-temperature impact energy is caused by the coarsening of (Ti, Mo)C precipitates.

中文翻译：

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淬火温度对新型中碳钛钼马氏体钢组织演变和强度-韧性的影响

同时提高高强度钢的强度和韧性是一项具有挑战性的任务。在此，开发了一种新型中碳 Ti-Mo 马氏体钢。研究了淬火温度对组织演变和强度-韧性的影响。进行显微组织和析出分析以阐明在开发的钢中提高强度-韧性的可能原因。添加 Ti 和 Mo 后，马氏体钢在 –40 °C 下产生 ≈1700 MPa 的高抗拉强度和 43 J 的冲击能量。强度和韧性的提高归因于通过热机械控制工艺 (TMCP) 和淬火和回火 (Q-T) 工艺相结合的更好的晶粒细化强化和沉淀强化。尽管在 850-910 °C 温度范围内淬火的含 Ti−Mo 马氏体钢的强度没有明显变化，但在 910 °C 的较高淬火温度下，含 Ti−Mo 马氏体钢的冲击能明显降低C。低温冲击能的降低是由 (Ti, Mo)C 析出物的粗化引起的。