Al_(3)Ti/A356复合材料微观组织及力学性能研究  

Microstructure and Tensile Properties of Al_(3)Ti/A356 Composite

作　　者：李亚龙 董志武 陈咪 刘志伟 余申卫[2] 何源[2] 尚金翅 LI Yalong;DONG Zhiwu;CHEN Mi;LIU Zhiwei;YU Shenwei;HE Yuan;SHANG Jinchi(State Key Laboratory for Mechanical Behavior of Materials,School of Materials Science and Engineering,Xi'an Jiaotong University,Xi'an 710049,China;CSSC NO.12 Research Instiute,Xingping 713102,China;Shandong Jinma Automotive Equipment Technology Co.,Ltd.,Linyi 276000,China)

机构地区：[1]西安交通大学材料科学与工程学院金属材料强度国家重点实验室,陕西西安710049 [2]中国船舶重工集团公司第十二研究所,陕西兴平713102 [3]山东金马汽车装备科技有限公司,山东临沂276000

出　　处：《铸造技术》2023年第6期553-560,共8页Foundry Technology

基　　金：国家自然科学基金(51974224,51604211);陕西省自然科学基金(2020JM-047);临沂市“揭榜制”“组阁制”项目(2021JB003)。

摘　　要：采用原位铸造法将Al_(3)Ti颗粒与铝基体复合可制备出高比强度的Al_(3)Ti/Al复合材料。原位Al_(3)Ti相易生成大尺寸长杆状颗粒且易团聚,降低熔体铸造性能并造成铸造缺陷。将超声处理工艺与原位铸造法结合,借助超声的空化和声流效应可有效分散并细化Al_(3)Ti颗粒,从而制备出组织均匀及性能优异的Al_(3)Ti/Al复合材料。本文以Al和K2TiF6为反应体系,通过超声辅助熔盐法制备出10%Al_(3)Ti/Al(质量分数)中间合金,在此基础上采用超声辅助重熔稀释法可制备出组织均匀及力学性能良好的5%Al_(3)Ti/A356(质量分数)复合材料,并对其微观组织和力学性能进行分析。结果表明,向A356基体中加入5%(质量分数)Al_(3)Ti,能够显著细化晶粒,α-Al平均晶粒尺寸从250μm细化为135μm,降低了46%;T6热处理态复合材料的屈服强度、抗拉强度和伸长率分别为232 MPa、287 MPa、3.5%,相比于A356合金分别提高了10.4%、12.5%、94.4%。An Al_(3)Ti/Al composite with high specific strength can be prepared by combining Al_(3)Ti particles and an Al matrix.The large Al_(3)Ti phase in the Al melt decreases castability and subsequently increases the casting defects.The research draws a probable solution to this issue such as redistribution of Al_(3)Ti particles by ultrasonic treatment.By combining ultrasonic treatment with in-situ casting,under the effect of ultrasonic cavitation and acoustic flow,the in-situ Al_(3)Ti particles are dispersed uniformly and finer.Hence,Al_(3)Ti/Al composites with homogeneous microstructure and excellent properties can be prepared by using the high-intensity ultrasound.The 10%Al_(3)Ti/Al(mass fraction)master alloy was prepared by ultrasound assisted molten salt method.Then,a 5%Al_(3)Ti/A356(mass fraction)composite with a homogeneous microstructure and good tensile properties was fabricated from the Al-K2TiF6 system via an ultrasound assisted remelting and dilution approach.The microstructure and tensile property of the composite have been investigated.The results indicate that theα-Al grains in the A356 alloy decrease from 250μm to 135μm(a 46%decrease)by adding 5%(mass fraction)Al_(3)Ti particles.Moreover,the yield strength,ultimate tensile strength and elongation of the composite after T6 heat treatment are 232 MPa,287 MPa and 3.5%(improved by 10.4%,12.5%and 94.4%,respectively,in comparison with the A356 alloy).

关 键 词：Al_(3)Ti/A356复合材料 超声 重熔稀释 微观组织 力学性能 

分 类 号：TB33[一般工业技术—材料科学与工程]