Powder Metallurgical Processing of Ultra-Hard Materials: Properties of AIMgB_(14) Prepared by High-Energy Zoz Milling

摘要

Recent interest in the relationship between microstructure and hardness has motivated numerous studies on a variety of material systems. In particular, the extreme hardness reported in composites based on AIMgB_(14) is thought to be due to a combination of high hardness in the matrix phase and a highly refined microstructure, obtained through mechanical alloying. The need to produce kilogram quantities of AIMgB_(14) prompted an assessment of the processing characteristic of the high-energy Zoz "Simoloyer" CM-01 in comparison with comparable research-scale material obtained from high-energy Spex milling. Powder was sampled from both milling devices and characterized by x-ray diffraction, SEM, and photon-correlation spectroscopy particle size analysis. Specimens were consolidated by hot pressing under vacuum or inert gas, and the microstructure of both types of compacts was characterized by optical and electron microscopy. It was found that the powder produced by the Zoz mill after 16 hours of milling was comparable to that obtained in a Spex mill after 12 hours. Powder from both processing routes was found to be sinterable, and resulted in a favorable microstructure for high hardness. It is concluded that the Zoz mill is a promising technology for large-scale processing of this new ultra-hard material.