In order to investigate the formation of AlN, mechanical alloying was carried out in and atmosphere. Differential thermal analysis (DTA), x-ray diffraction (XRD) and chemical analysis were carried out to examine the formation behavior of aluminum nitrides. No diffraction pattern of AlN was observed in XRD analysis of the as-milled powders in atmosphere. However, DTA and chemical analysis indicated that the precursors for AlN were formed in the Al powders milled in atmosphere. The AlN precursors transformed to AlN after heat treatment at and above . It was considered that the reaction between Al and was possible by the formation of fresh Al surface during mechanical alloying of Al powders.

Mechanical alloying using high-energy ball mill and subsequent spark plasma sintering (SPS) process was applied to understand mechanical alloying processing of Al-Fe alloy system. The thermal stability of mechanically alloyed Al-Fe alloy was intended to be enhanced by SPS process. Various analytical techniques including particle size analysis, density measurement, micro-Vickers hardness test, SEM, TEM, and X-ray diffractometry were adopted to find optimum processing conditions for mechanical alloying and subsequent SPS and to estimate thermal stability of the prepared alloy. It was found from the treatment of mechanically alloyed Al-8wt.%Fe powder mixture that needle-shaped precipitates was formed in the Al-Fe matrix, and the alloy compact showed enhanced densification and reached its full density with little loss of its fine microstructure. After heat treatment at , it was also shown that the thermal stability of Al-8wt.%Fe alloy fabricated in the present study was enhanced, which was due to its fine microstructure developed by fast densification of SPS.

Mechanical alloying using high-energy ball mill and subsequent spark plasma sintering (SPS) process was applied to Al-Fe-Cr and Al-Fe-Mo powder mixture to investigate effects of Cr and Mo addition on thermal stability of Al-Fe, and thereby to enhance its thermal stability up to . Various analytical techniques including micro-Vickers hardness test, SEM, TEM, X-ray diffractometry and corrosion test were carried out. It was found that addition of Cr and Mo to Al-Fe system played a role of grain growth inhibitor of matrix Al and some precipitates such as during SPS and subsequent heat treatment. The inhibition of grain growth resulted in increased Vickers hardness and thermal stability up to comparing to those of Al-Fe alloy system.

Four different mechanical alloying(MA) processes were employed to fabricate very fine intermetallic compound particles dispersed Al composite materials(MMC) with Al-4at.%Zr composition. Phase transformations including phase stability during MA and heat treatment processes were investigated. Part of Zr atoms were dissolved into Al matrix and part of them reacted with hydrogen produced by decomposition of PCA(methanol) to form hydride during first MA process. These hydrides disappeared when alloy powders were heat treated at . Stable dispersoids with structure were formed by heat treating the mechanically alloyed powders at . On the other hand, metastable dispersoids with structure were formed during first MA of powers with Al-25at.%Zr composition. These metastable dispersoids transformed to stable with structure when heat treated above .

Recently, it has been found that mechanical alloying (MA) facilitates the nanocomposites formation of metal-metal oxide systems through solid-state reduction during ball milling. In this work, we studied the MA effect of FeO-M (M = Al, Ti) systems, where pure metals are used as reducing agents. It is found that composite powders in which O and TiO are dispersed in -Fe matrix with nano-sized grains are obtained by mechanical alloying of FeO with Al and Ti for 25 and 75 hours, respectively. It is suggested that the large negative heat associated with the chemical reduction of magnetite by aluminum is responsible for the shorter MA time for composite powder formation in FeO-Al system. X-ray diffraction results show that the reduction of magnetite by Al and Ti if a relatively simple reaction, involving one intermediate phase of FeAlO or FeTiO. The average grain size of -Fe in Fe-TiO composite powders is in the range of 30 nm. From magnetic measurement, we can also obtain indirect information about the details of the solid-state reduction process during MA.

1980년대 후반부터 집중적으로 연구되어온 기계적 합금화 공정 기술은 이제 단순화합물 조성의 합금화공정 뿐 만아니라 기계화학적(Mechanochemical) 방법으로까지 진보되어 다양한 시스템으로의 응용기술로까지 발전하게 되었다 더욱이 최근 나노기술의 한고상 제조기술로서도 역할을 하게 되는 기계적 합금화 공정 기술은 21세기에 있어서도 본문에서 연급한 바와 같은 고온용 고장도 Al 합금제조 외에도 나노결정립 분말, 자성재료, 에너지전환/저장기능재료, 준