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采用粉末冶金+热挤压法制备了纳米B_4C_P(n-B_4C_P)体积分数分别为2%,4%,6%的n-B_4C_P/2009Al复合材料,运用光学显微镜(OM)、扫描电镜(SEM)、透射电镜(TEM)、X射线衍射(XRD)和维氏硬度测量仪等仪器研究了n-B_4C_P体积分数对n-B_4C_P/2009Al复合材料的微观组织、固溶时效行为及力学性能的影响。结果表明:复合材料经热挤压后组织致密均匀,n-B_4C_P体积分数的增加没有明显增加复合材料孔隙率;复合材料经495℃固溶1 h处理后,仅存在少量析出相(Al_2Cu)残留基体中;经固溶淬火+175℃人工时效14 h后,n-B_4C_P体积分数为2%,4%,6%的n-B_4C_P/2009Al复合材料同时达到峰值硬度,比基体合金提前了2 h;利用TEM观察时效后的微观组织表明,n-B_4C_P的加入抑制了基体中析出相(Al_2Cu)的长大,大量细小析出相的存在使复合材料达到峰时效的时间提前;经最佳热处理工艺处理后,随着n-B_4C_P体积分数的增加,复合材料的抗拉强度先上升后下降,屈服强度始终呈上升趋势。高体积分数的n-B_4C_P有效地起到钉扎位错的作用,但是高体积分数n-B_4C_P产生的颗粒团聚现象导致复合材料在拉伸时提早开裂。
The nano-B_4C_P (n-B_4C_P) nano-B_4C_P / 2009Al composites with volume fractions of 2%, 4% and 6% were prepared by powder metallurgy and hot extrusion method. , Transmission electron microscopy (TEM), X-ray diffraction (XRD) and Vickers hardness tester. The effects of volume fraction of n-B_4C_P on the microstructure, solution aging behavior and mechanical properties of n-B_4C_P / 2009Al composites were investigated. The results show that the microstructure of the composite is dense and uniform after hot extrusion. The increase of the volume fraction of n-B_4C_P does not significantly increase the porosity of the composite. After the solution is melted at 495 ℃ for 1 h, only a small amount of residual phase (Al 2 Cu) In the matrix, the n-B_4C_P volume fraction of 2%, 4% and 6% of n-B_4C_P / 2009Al composites reached the peak hardness at the same time after solution quenching + 175 ℃ artificial aging for 14 h, . The microstructure after aging by TEM shows that the addition of n-B_4C_P suppresses the growth of the precipitated phase (Al 2 Cu) in the matrix. The presence of a large number of fine precipitates advances the time of peak aging of the composite ahead of time. The optimum heat treatment process With the increase of the volume fraction of n-B_4C_P, the tensile strength of the composites first increased and then decreased, and the yield strength always increased. The high volume fraction of n-B_4C_P effectively acts as a pinning dislocation, but the particle agglomeration resulting from the high volume fraction n-B_4C_P causes the composite to prematurely crack upon stretching.