Invar alloys that combine high strength with a low coefficient of thermal expansion (CTE) are urgently required for industrial applications. Based on the lower coarsening rate during aging and the CTE values of carbonitrides, a novel strategy is proposed to prepare carbonitrides by reducing carbon and increasing nitrogen to design high-strength and low-thermal-expansion invar alloys. The V(C, N) nanoprecipitate was introduced into the invar alloy, and its effects on the microstructure, thermal expansion behavior, and mechanical properties were investigated. The direct-aged alloy exhibited an enhanced tensile strength of 525 MPa and a ductility of 47.6%. The cold-deformation aging alloy achieved an enhanced tensile strength of 815 MPa while retaining 7.4% ductility and a low CTE value of 1.23×10 /°C. The V(C, N) nanoprecipitates effectively immobilized dislocations and grain boundaries, leading to a high dislocation density and small grain size in the alloy. The contributions of each strengthening mechanism were calculated, and the precipitation and dislocation strengthening were found to be the main mechanisms of strength enhancement. These results provide a novel approach for preparing high-strength and low-CTE invar alloys.

中文翻译：

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通过预制缺陷促进纳米沉淀到钉位错和晶界，以权衡殷钢合金的高强度和低热膨胀性


工业应用迫切需要兼具高强度和低热膨胀系数 (CTE) 的因瓦合金。基于时效过程中较低的粗化率和碳氮化物的CTE值，提出了一种通过减少碳和增加氮来制备碳氮化物的新策略，以设计高强度和低热膨胀殷瓦合金。将V(C,N)纳米沉淀物引入因瓦合金中，研究其对微观结构、热膨胀行为和力学性能的影响。直接时效合金表现出525MPa的增强拉伸强度和47.6%的延展性。冷变形时效合金的拉伸强度提高到了815MPa，同时保留了7.4%的延展性和1.23×10 /°C的低CTE值。 V（C，N）纳米沉淀有效地固定位错和晶界，导致合金中位错密度高和晶粒尺寸小。计算了各强化机制的贡献，发现析出强化和位错强化是强度增强的主要机制。这些结果为制备高强度、低CTE因瓦合金提供了一种新方法。