Microstructure and properties of the Ni-Al-B alloys after directional solidification

Abstract

Microstructure and Properties of the Ni-Al-B Alloys after Directional Solidification Ni-24Al, Ni-24Al-0.1B and Ni-24Al-0.24B alloys (at. %) were prepared by vacuum induction melting and by directional solidification at the rate of 50 mm/h and at the 1550 degrees C. After directional solidification, alloy microstructure consists of elongated grains of the gamma' phase. Alloy matrix also contains small amount of the gamma phase. There are no boron phases in these alloys. Process of directional solidification decreases an amount of the pores which the alloys contain after cast and modify their morphology. Microhardness of the alloys after directional solidification is lower then microhardness of the alloys after cast. However, there is no matrix softening of Ni-24Al alloy as a result of boron alloying.