原位自生TiB2/Al复合材料的组织与力学性能

采用钛盐与硼盐反应法成功制备原位自生TiB2/纯Al复合材料。利用扫描电子显微镜、透射电子显微镜和拉伸试验机研究不同粒子含量(质量分数为1%、2%和3%)对复合材料组织和力学性能的影响。结果表明:原位生成的TiB2粒子有矩形、近圆形和六边形三种形貌,尺寸为200~500 nm;粒子与Al基体界面洁净无反应层。随着粒子含量的增加,复合材料的强度随之升高,而伸长率则随之降低;当TiB2含量为3%时,屈服强度和抗拉强度分别达到78.1 MPa和102 MPa,相比于纯Al分别提高58%和43%,而伸长率降至32.5%,下降了24%。断口分析表明:随着TiB2粒子含量的增加,粒子团聚机率增加,在拉伸过程中,裂纹在粒子团聚处萌生并扩展,导致材料的塑性降低。

Microstructure and mechanical properties of in-situ TiB2/Al composites

The in-situ TiB2/pure Al composites were fabricated successfully by titanium salt and boron salt reaction process.The influences of TiB2 contents(1%,2%and 3%,mass fraction)on microstructure and mechanical properties were studied by scanning electronic microscopy,transmission electronic microscopy and tensile test machine.The results show that the morphologies of TiB2 particles present in rectangular,nearly rounded and hexagonal with the size of about 200?500 nm.And the interface between TiB2 particles and Al matrix is clean.Tensile test results indicate that the strength significantly increases while the elongation decreases with the increasing of TiB2 particles.The yield strength(YS)and ultimate tensile strength(UTS)of TiB2/pure Al composite at 3%TiB2 particles reach 78.1 MPa and 102 MPa,respectively,while the elongation reduces to 32.5%.The composite has achieved 58%and 43%improvement,respectively,in YS and UTS with respect to pure Al,while compromising 24%in ductility.The fractography reveals that agglomerations happen severely with increasing the TiB2 particles amounts,and the crack propagation tends to begin from the agglomerations,which leads to the decreasing of ductility.