Abstract

In the present work, x wt% B₄C (x = 2, 4, 6, 8) and 2 wt% BN reinforced aluminum 6061 metal matrix hybrid composites were synthesized by mechanical milling for 10 h. The milled powders were consolidated by cold uniaxial compaction at various compression pressure (200–800 MPa) and then sintered at various temperatures (400–600 °C). Microstructural characterization of the milled powders and the fabricated composites were performed by X-ray diffraction, scanning electron microscope, and energy dispersive spectroscopy techniques. The effect of B₄C/BN reinforcements on the densification of the milled powders was studied in terms of compressibility and sinterability. The mechanical properties, specifically the green compressive strength, and hardness of the composites were also investigated. The empirical relations formulated by Heckel, Panelli-Filho, and Ge were used to plot the compressibility curves of the developed composites to study the compressibility behavior of the milled powders. The densification co-efficient (K) of the powders and sinterability behavior of the composites decreased with an increase in B₄C reinforcement. B₄C particles prevented the grain growth by seizing the grain boundary, resulting in refinement of grains and enhancement in mechanical properties The maximum compressive strength of 249 MPa and hardness of 184 HV was observed for the sample Al6061–8 wt% B₄C–2 wt% BN compressed at 800 MPa and sintered at 600 °C.

Graphic Abstract

摘要

在本工作中，通过机械研磨10 h合成了x wt％的B ₄ C（x = 2、4、6、8）和2 wt％的BN增强铝6061金属基杂化复合材料。研磨后的粉末在各种压缩压力（200–800 MPa）下通过冷单轴压实进行固结，然后在各种温度（400–600°C）下烧结。通过X射线衍射，扫描电子显微镜和能量色散光谱技术对研磨后的粉末和制成的复合材料进行微观结构表征。B ₄的作用从可压缩性和可烧结性方面研究了研磨粉致密化过程中的C / BN增强材料。还研究了复合材料的机械性能，特别是未压缩强度和硬度。使用由Heckel，Panelli-Filho和Ge得出的经验关系来绘制开发的复合材料的可压缩性曲线，以研究研磨粉的可压缩性。随着B ₄ C增强，粉末的致密系数（K）和复合材料的烧结性能降低。B ₄C颗粒通过抓住晶界阻止了晶粒的生长，从而导致晶粒的细化和机械性能的增强对于样品Al6061–8 wt％B ₄ C–2 wt ，样品的最大抗压强度为249 MPa，硬度为184 HV。％BN在800 MPa下压缩并在600°C烧结。

图形摘要