原位颗粒增强A357复合材料的制备及组织性能

Fabrication and Properties of In-situ Synthesized Particle Reinforced A357 Composites

以A357-Na_2B_4O_7-K_2ZrF_6体系与A357-KBF_4-K_2ZrF_6体系合成原位颗粒增强A357铝基复合材料。结果表明,增强相含量小于1.5%,仅合成Al_3Zr一种增强相,增强相含量为2%时,ZrB_2与Al_3Zr增强相同时合成;A357-K_2ZrF_6-KBF_4体系合成原位颗粒增强复合材料时ZrB_2颗粒为增强相;A357-Na_2B_4O_7-K_2ZrF_6体系合成复合材料的抗拉强度随增强相含量的增加呈先增加后减小的趋势,最大值为182 MPa,是基体的1.17倍;反应体系A357-K_2ZrF_6-KBF_4合成复合材料抗拉强度随增强相含量增加而呈上升趋势,最大值为192 MPa,是基体的1.24倍;两种复合材料断口上存在大量韧窝,表明断裂方式均为塑性断裂。

In-situ A357 composites were synthesized in A357-Na2B4O7-K2ZrF6 system and A357-KBF4-K2ZrF6 system by direct melt reaction.The results show that as the volume fraction less than 1.5%,only Al3Zr reinforcement can be observed,while as volume fraction more than 2%,both ZrB2 and Al3Zr reinforcements can be fabricated in system A357-Na2B4O7-K2ZrF6.Only ZrB2 reinforcement can be synthesized in system A357-K2ZrF6-KBF4,and with volume fraction increase,the number of ZrB2 reinforcements is increased.The tensile strength of composites synthesized in A357-Na2B4O7-K2ZrF6 system is decreased firstly and then increased,where the highest value reaches 182 MPa,which is 1.17 times of the matrix,while the tensile strength of composites synthesized in A357-K2ZrF6-KBF4 system presents an increasing trend,where the highest value is 192 MPa,which is 1.24 times of the matrix.In addition,fracture mechanism of the composites from both systems is characterized by plastic fracture.