SiC_p分布对SiC_p/2024Al复合材料组织和性能及变形行为的影响  

Effects of SiCp distribution on microstructure,mechanical properties and deformation behavior of SiCp/2024Al composites

作　　者：薛鹏鹏 邓坤坤[1] 聂凯波[1] 史权新[1] 刘力 XUE Pengpeng;DENG Kunkun;NIE Kaibo;SHI Quanxin;LIU Li(College of Materials Science and Engineering,Taiyuan University of Technology,Taiyuan 030024,China;Xingxian Economic Development Zone Aluminum Magnesium New Material Research and Development Company Limited,Luliang 033603,Shanxi,China)

机构地区：[1]太原理工大学材料科学与工程学院,太原030024 [2]兴县经开区铝镁新材料研发有限公司,山西吕梁033603

出　　处：《材料工程》2024年第4期164-175,共12页Journal of Materials Engineering

基　　金：国家重点研发计划青年科学家项目(2021YFB3703300);国家自然科学基金(52271109);吕梁市重点研发项目(Rc2020-108)。

摘　　要：采用半固态搅拌铸造法制备出SiC_(p)/2024Al复合材料,并通过热挤压和多向锻造(MDF)的多步变形调控SiC_(p)的分布,研究SiC_(p)分布对SiC_(p)/2024Al复合材料组织和性能的影响。研究结果表明:热挤压变形促使SiC_(p)沿挤压方向(ED)排布;而经过多向锻,SiC_(p)分布得到显著改善,由定向排布转变为均匀分布。经过1MDF后,沿ED定向排布的SiC_(p)向无序分布转变,同时材料的力学性能急剧下降。3MDF后SiC_(p)分布均匀性提高,材料的力学性能大幅提高。随着锻造道次增加至6道次,虽然SiC_(p)分布均匀性进一步提高,但伴随着部分SiC_(p)发生破碎,材料的力学性能下降。其中,当锻造次数为3时,复合材料的力学性能最优,其屈服强度、极限抗拉强度和伸长率分别为264,387 MPa和7%。与定向分布的复合材料相比,均匀分布的SiC_(p)可有效缓解局部应力集中,合金基体能存储更多的位错。此外,当SiC_(p)分布均匀性提高时,也伴随着Al_(2)Cu相的细化。弥散分布的Al_2Cu相阻碍了位错的滑移,导致均匀分布的复合材料具有更高的加工硬化率和内应力。为了研究SiC_(p)分布对复合材料加工软化行为的影响,对复合材料进行循环应力松弛实验。在应力循环过程中,由于均匀分布的SiC_(p)和弥散分布的Al_(2)Cu相,导致均匀分布SiC_(p)/2024Al复合材料的抗应力松弛性能更好。SiC_(p)/2024Al composite was prepared by semi-solid stirring casting,and the distribution of SiC_(p) was regulated by multi-step deformation of hot extrusion and multi-direction forging(MDF).The effects of SiC_(p) distribution on the microstructure and properties of SiC_(p)/2024Al composite ware studied.The results show that hot extrusion deformation cause SiC_(p) to distribute along the extrusion direction(ED).After multi-directional forging,SiC_(p) distribution is improved significantly,and it changes from directional distribution to uniform distribution.After 1MDF,the SiC_(p) distribution along the ED changes to disordered distribution,and the mechanical properties of the material are sharply decreased.After 3MDF,the distribution uniformity of SiC_(p) is improved,and the mechanical properties of the material are greatly improved.When the forging passes increase to 6,the distribution uniformity of SiC_(p) is further improved,the mechanical properties of the material decrease with the partial SiC_(p) breaking.When the forging number is 3,the mechanical properties of the composite are optimal,with yield strength,ultimate tensile strength and elongation are 264 MPa,387 MPa and 7%,respectively.Compared with the directionally distributed composite,the uniform distribution of SiC_(p) effectively relieves the local stress concentration,and the matrix alloy stores more dislocation.In addition,when the distribution uniformity of SiC_(p) is improved,the Al_(2)Cu phase is also refined.The diffuse distribution of Al_(2)Cu phase hinders the slip of dislocation,resulting in a uniformly distributed composite with a higher work hardening rate and internal stress.In order to study the effect of SiC_(p) distribution on softening behavior of composites,cyclic stress relaxation experiments are carried out.In the process of stress cycling,the uniformly distributed SiC_(p)/2024Al composites with uniform distribution of SiC_(p) and Al_(2)Cu phases exhibit a better stress relaxation resistance.

关 键 词：SiC_p分布 铝基复合材料 软化行为 多向锻造 加工硬化 

分 类 号：TB331[一般工业技术—材料科学与工程]