摘要
针对传统钼合金断裂韧性低、强度与韧性难以协同提升的问题,本文提出采用MAX相材料Ti_(3)AlC_(2)作为强韧化相,通过粉末冶金法制备不同Ti_(3)AlC_(2)含量的钼基复合材料。结果表明:当Ti_(3)AlC_(2)添加量为0.3%(质量分数,下同)时,合金综合性能最优,其抗拉强度达527.7 MPa,延伸率为20.56%,断裂韧性为28.3 MPa·m 1/2;过量添加导致第二相团聚与孔隙率增加,致密度降至93.7%,力学性能显著下降。Ti_(3)AlC_(2)通过高温分解原位生成Mo_(2)C、TiO_(2)及Ti-Al化合物,协同细晶强化、弥散强化与固溶强化提升强度;残余Ti_(3)AlC_(2)的层状结构通过诱导裂纹偏转与分叉等机制提高韧性,突破传统强化相强度与韧性此消彼长的问题。该研究为开发兼具高强度与高韧性的先进钼合金材料提供了新思路。
To address the low fracture toughness and the mutually exclusive relationship between strength and toughness in conventional molybdenum alloys,this study proposes the utilization of MAX phase material Ti_(3)AlC_(2)as a strengthening and toughening phase.Molybdenum-based composites with varying Ti_(3)AlC_(2)contents were fabricated via powder metallurgy.The results demonstrate that the composite with 0.3%cmass fraction Ti_(3)AlC_(2)exhibits optimal comprehensive properties:a tensile strength of 527.7 MPa,elongation of 20.56%,fracture toughness of 28.3 MPa·m 1/2.Excessive addition led to particle agglomeration and increased porosity,reducing the relative density to 93.7%and significantly degrading mechanical properties.The high-temperature decomposition of Ti_(3)AlC_(2)generates in situ Mo_(2)C、TiO_(2),and Ti-Al compounds,which synergistically enhance strength through grain refinement,dispersion strengthening,and solid solution strengthening.Meanwhile,the residual layered Ti_(3)AlC_(2)phase improves toughness by inducing crack deflection and branching along interlayer interfaces,overcoming the conventional trade-off between strength and toughness.This study provides a novel strategy for developing advanced molybdenum alloys with high strength and exceptional fracture resistance.
作者
杜风顺
王德志
吴壮志
刘新利
段柏华
DU Fengshun;WANG Dezhi;WU Zhuangzhi;LIU Xinli;DUAN Bohua(School of Materials Science and Engineering,Central South University,Changsha 410083,Hunan,China;State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,Hunan,China)
出处
《中国钼业》
2025年第4期64-72,共9页
China Molybdenum Industry
基金
国家重点研发计划(2022YFB3705402)。
