纳米B_4C_P/2009Al复合材料固溶时效行为与力学性能  

Solution Treatment and Aging Behavior and Mechanical Properties of Nano-B_4C_P/2009Al Composite

作　　者：刘越[1] 屈光[1] 

机构地区：[1]东北大学,辽宁沈阳110819

出　　处：《稀有金属材料与工程》2017年第10期2950-2956,共7页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(51334004);辽宁省科技创新重大专项(201404001)

摘　　要：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。Nano-B_4C_P particulates（n-B_4C_P） reinforced 2009Al matrix composites with different reinforcement volume fractions（0, 2%, 4% and 6%） were fabricated by powder metallurgy combined with hot extrusion. The effects of different volume fractions of n-B_4C_P on microstructure, solution and aging behavior and mechanical properties of n-B_4C_P/2009Al composites were studied by optical microscopy（OM）, scanning electron microscopy（SEM）, transmission electron microscope（TEM）, X-ray diffraction（XRD）, Vicker hardness measuring instrument and so on. The results show that the n-B_4C_P is uniformly dispersed in the composites after hot extrusion process. The best solution temperature and time of the composites are 495 °C and 1 h, the resolution of second phase particles（Al_2Cu） are dissolved back into the matrix with only a small amount remaining in the matrix during solution treatment process. n-B_4C_P/2009Al composites with different volume fractions of n-B_4C_P treated at 495 °C for 1 h and then aged at 175 °C for 14 h almost simultaneously reach the peak hardness, and the aging peak time decreases by 2 h compared to matrix alloy. After peak aging, the micro-structure of composites was observed by TEM, indicating that the growth of precipitation Al_2Cu is strongly restrained due to the addition of n-B_4C_P particulates. Compared to the matrix alloy, the composites with higher density of finer precipitates lead to an earlier attainment in the peak aging condition. After the optimum heat treatment process, the tensile strength of the composites increases at first and then decreases with the increasing of n-B_4C_P volume fraction, while the yield strength always increases. High volume fraction of n-B_4C_P effectively plays the role of pinning dislocations, but the agglomeration of high volume fraction of n-B_4C_P results in composites＇ early cracking.

关 键 词：纳米B4CP 2009Al复合材料 固溶处理 时效行为 力学性能 

分 类 号：TB333[一般工业技术—材料科学与工程]