CuZr/AlN纳米复合材料的组织与性能(英文)

采用粉末冶金方法制备高强高导铜合金基纳米复合材料(CuZr/AlN)。采用光学显微镜(OM)和高分辨率透射电镜(HRTEM)等方法研究不同烧结工艺对复合材料组织与性能的影响,研究固溶时效对CuZr/AlN力学性能的影响。结果表明:试样的组织致密,晶粒大小在0.2μm左右;试样的布氏硬度随着复压制压力和烧结温度的升高而升高;试样的布氏硬度开始随着锆含量的增加而升高,但当锆颗粒含量大于0.5%时,复合材料的布氏硬度开始降低。试样的抗弯强度随着复压制压力和烧结温度的升高而提高,抗弯强度在锆含量为在0.5%时最大。900°C固溶后的布氏硬度比固溶前的布氏硬度低,试样在500°C和600°C时效后,布氏硬度增加,在700°C发生过时效现象。     

Zr对Cu-15Cr合金铸态组织及热稳定性的影响

为了研究Zr对Cu-Cr形变原位复合材料组织和性能的影响,采用真空中频感应熔炼技术,制备了Cu-15Cr和Cu-15Cr-0.24Zr合金。利用扫描电子显微镜(SEM)、能谱仪(EDS)、透射电子显微镜(TEM)等表征手段,研究了Zr对Cu-15Cr合金铸态组织及不同温度退火1h后的组织的影响;对两种试验合金进行了冷轧变形,对最终变形量下的试验合金的热稳定性进行了研究。结果表明:Zr的加入,使合金的铸态组织中生成了薄片状的Cu Zr金属间化合物;抑制了共晶Cr相的生成,使共晶Cr含量远低于Cu-15Cr合金,同时,细化了枝晶Cr的尺寸;显著提高了合金的热稳定性,使其在550℃退火1 h后的抗拉强度提高了100 MPa。并通过对试验合金凝固过程的吉布斯自由能(ΔG_(mix))的计算,得出Zr的加入降低了Cu-15Cr合金的液相分离温度,减小了Cu-15Cr合金在凝固过程中动态平衡下的形核驱动力,因此抑制了共晶Cr的生成,这与试验观察到的铸态组织结果一致。     

Structure and Mechanical Properties of Cu/AlN Nano- composites with High Strength and High Conductivity

采用粉末冶金方法制备高强高导铜合金基纳米复合材料(Cu/AlN),用光学显微镜、TEM和SEM等方法研究不同工艺条件如温度、压力、复压压力及复烧温度对复合材料组织与性能的影响。结果表明:烧结后的试样密度随压力、烧结温度的升高而增大;试样布氏硬度随复压制压力和烧结温度的升高而升高;试样布氏硬度开始随着纳米AlN颗粒的含量增加而升高,但当纳米AlN颗粒质量分数大于0.5%时,复合材料的布氏硬度开始下降。试样的抗弯强度随复压制压力和烧结温度的升高而提高。     

Actively brazed alumina to alumina joints using CuTi,CuZr and eutectic AgCuTi filler alloys

Al₂O₃ to Al₂O₃ joints were produced using a one stage active brazing technique based on CuTi, CuZr and AgCuTi active brazing alloys. Single- and double-butt joints were used for microstructural (light and scanning electron microscopy and X-ray diffraction) and mechanical property (double shear test) studies, respectively. The joints produced with CuZr filler alloys (containing 2%, 4%, 6% and 8% Zr, wt%) showed low shear strengths (0.2–0.4 MPa) due to the presence of ZrO₂ at the braze–substrate interface and failed in mode I crack opening. Higher shear strengths of 15–24 and 42 MPa were obtained by using CuTi filler alloys (containing 2%, 4%, 6%, 8% and 10% Ti, wt%) (mode II/mode III dependent on the Ti content) and the eutectic (Ag–27 wt% Cu–5 wt% Ti) alloy, respectively. The high shear strengths were attributed to the small amount of Cu₂(AlTi)₄O at the braze–substrate interface and led, in the case of the ternary alloy, to the failure of the substrate rather than the braze (mode III axial splitting).