原位合成TiB_2对B_4C/2024Al合金复合材料组织与力学性能的影响  

Effect of in situ synthesized TiB_2 on microstructure and mechanical properties of B_4C/2024 Al alloy composites

作　　者：周飞[1] 夏长清[1] 曾凡浩[2] 牛国帅[1] 

机构地区：[1]中南大学材料科学与工程学院,长沙410083 [2]中南大学粉末冶金国家重点实验室,长沙410083

出　　处：《粉末冶金材料科学与工程》2012年第4期457-461,共5页Materials Science and Engineering of Powder Metallurgy

基　　金：总装备部预研基金资助项目(51312010311)

摘　　要：在B4C粉末中加入5%高纯TiO2,经过压制和烧结制备B4C-TiB2陶瓷预制体,然后在氩气气氛中1 200℃下浸渗2024铝合金制得B4C-TiB2/Al合金复合材料。对该复合材料进行力学性能测试、X射线衍射分析、显微组织观察和断口分析。结果表明:该复合材料主要由B4C,Al,Al3BC和AlB2相组成,原位合成的TiB2使B4C/Al合金复合材料的抗弯强度和断裂韧性显著提高,分别达到361 MPa和7.49 MPa m1/2,增幅分别为14.6%和11.5%,但密度变化很小。原位合成TiB2使B4C/Al合金复合材料的抗弯强度和断裂韧性提高主要来源于金属铝塑性变形的裂纹桥接机制、TiB2细化晶粒及微裂纹引起的主裂纹偏转分叉机制。B4C-TiB2/Al composites were fabricated at 1 200 ℃ by pressureless melt infiltration of 2024 aluminum alloy under Ar atmosphere into porous BnC green compacts added with 5% （mass fraction） high purity TiOz which were prepared by presintering. Mechanical properties of the composites were tested. The phase composition and microstructure of B4C-TiBz/A1 alloy composites were determined by X-Ray diffraction （XRD） and scanning electron microscope （SEM）. The results show that main phases of the composites are B4C, Al, A13BC and A1B2. The in-situ synthesized TiB2 can effectively improve the mechanical properties of the B4C-TiB2/A1 composites. The value of bending strength and fracture toughness of BaC-TiB2/Al alloy composites are 361 MPa and 7.49 MPa＇M1/2 which are 14.6% and 11.5% higher than that of BaC/A1 composites. The mechanisms of mechanical property increasing include crack bridging mechanism of A1 plastic deformation, TiBz grain refinement and crack deflection and branching.

关 键 词：B4C-TiB2/Al复合材料 原位合成 无压浸渗 断裂韧性 

分 类 号：TB333[一般工业技术—材料科学与工程]