摘要
对Al—TiO2-B2O3系利用放热弥散(XD)反应法合成了铝基复合材料.当B2O3/TiO2摩尔比为0时,增强相由α-Al2O3颗粒和棒状物Al3Ti组成,抗拉强度和延伸率分别为250.4 MPa和4.0%,断口中有的棒状物自身开裂,断裂由Al3Ti自身萌生裂纹,并沿其解理面扩展至界面引起.加入B2O3后,棒状物Al3Ti减少,基体晶粒细化,强度和延伸率同步提高;当B2O3/TiO2摩尔比为1时,Al3Ti基本消失,抗拉强度和延伸率分别提高到320.8 MPa和10.6%,断口形貌由细小韧窝组成.随着实验温度的增加,延伸率进一步提高,拉伸强度则随之下降,棒状物Al3Ti因与基体的界面结合强度降低而与基体中脱离,表明Al3Ti对复合材料的性能提高不利. 723 K时,延伸率上升至20.5%,抗拉强度下降至85.6 MPa.
Structure, mechanical properties and fracture mechanism of the composites fabricated by XD（exothermic dispersion） method in Al-TiO2-B2O3 system were investigated. When the B2O3/TiO2 mole ratio is zero, the reinforcements of the composites are α-Al2O3 and Al3Ti, the ultimate tensile strength （σb） and elongation （δ） are 250.4 MPa and 4.0% respectively （room temperature）. The fracture mechanism of the composite is characterized by cracks initiating firstly in Al3Ti rods and then propagating to the interface. When the B2O3/TiO2 mole ratios increases, the amount of Al3Ti phase decreases, σb and δ increase. When the B2O3/TiO2 mole ratio reaches 1, the Al3Ti phase almost eliminates, σb and δ increased to 320.8 MPa and 10.6%, respectively. The tensile fracture surface is composed of all fine ductile dimples. With increasing the test temperature, σb decreases and δ increases. The Al3Ti rods are pulled out from the matrix due to decreasing of the interface strength at high temperature. Therefore, the Al3Ti phase is not of benefit to strengthening the composites. At 723 K, δ increases to 20.5%, but σb decreases to 85.6 MPa.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2005年第8期829-834,共6页
Acta Metallurgica Sinica
基金
国家高技术研究发展计划资助项目2002AA331010
关键词
热弥散反应
铝基复合材料
力学性能
XD （exothermic dispersion reaction）, aluminum matrix composite, mechanicalproperty
