The Research On Mo-Al Eutectic Mechanical Alloy Were Fabricated With A Solid-liquid Reaction Milling And Influence Of PCA On The Process Of The Solid-liquid Reaction Milling

A novel solid-liquid reaction milling technique, was selected to prepare intermetallic compound powders by reacting the medium with metal metal at a certain temperature range. Furthermore, some element powders with the same composition as the milling medium were added to accelerate the reaction. In the reaction milling course, some milling ball with milling meidium will bonding together then prevent the reaction from going on. This paper selected the Mo, Ni as the balls, and Al metal as the liquid metal. The identification of different phases is examined by D5000 X-ray diffraction, and the microstructure is analyzed by JSM-6700F scanning electron microscopy.Firstly, Mo-Al alloy system was inverstigated, the phase formation regularity and the characteristic of the as formulate powders under different temperature and different time of the reaction milling. The conductions are drawn as follows:(1)For the Mo-Al binary alloy system, Mo balls were adopted to mill Al melt, the weight ratio of ball-to-material was 20:1 and the rotation speed of was 80rpm. Al₁₂Mo, A₁₅Mo, Al₂₂Mo₅ and Al₁₇Mo₄ intermetalli compounds cylinder phase were obtained by milling Al melt at 943K. Al₁₇Mo₄ compound powder was obtained at 993k for 48 hours or at 1073K for 24 hours, and higher temperature can accelerate the formation of Al₁₇Mo₄ powder.(2) The Al₁₂Mo,A₁₅Mo,Al₂₂Mo₅ phase in the as formed powders were unstable, and it were easyly to react with the Mo ballsto become intermetallic compound alloy phase reach in Mo.(3) Longer milling time can lead to finer powders.Secondly, the solid-liquid reaction milling processing for Ni-Al system was investigated. The milling temperature wse kept at 973K and the milling time was 10h. HCl,NaCl,KCl,Na₂SO₄ and stearic acid was selected as the process control agent(PCA) to controlling the bonding between the milling balls. The conductions are drawn are following:(1) PCAs can accelerate the reaction process and increase the powders product and weak the bounding between the balls, the melt and the as formed powders.(2) Excessing PCAs addition will decrease the powders product. The powders product is the lowest when adding 5ml HCl as PCA, while adding 2%NaCl, KCl,Na₂SO₄ as PCA the powders product is highest and main with Ni₂Al₃.(3) The addition of PCA can produce finer powders with uniform partical size.