Effect of directional solidification on the structure and properties of Ni3Al-based alloy single crystals alloyed with W, Mo, Cr, and REM

Effect of directional solidification on the structure and properties of Ni3Al-based alloy single crystals alloyed with Cr, Mo, W, Ti, Co, Re, and REM

“…Three systems of lines are also visible in a longitudinal (110) polished section; however, two of them are par allel to each other and the third system is perpendicu lar to them. The same dependence of the morphology of dendrite arms on the orientation of a single crystal is observed for an Ni 3 Al based VKNA 1V alloy [13] and fcc nickel superalloys [14].…”

“…When studying the strength and the high tempera ture strength of other Ni 3 Al based alloys, we found that they were maximal for [111] single crystals [7,8,11,13]. Therefore, in this work we focused on an anal ysis of single crystals with this CO.…”

“…Therefore, in this work we focused on an anal ysis of single crystals with this CO. In [13], we showed that the [111] single crystals grown by HGDS at a solidification gradient G = 150°C/min and a solidifi cation rate R = 10 mm/min had the following impor tant properties: a high high temperature strength over the entire temperature range under study, a high low temperature plasticity, a moderate high temperature plasticity, and no plasticity drop at 800°C (which is characteristic of single crystals with other COs). As a result, we were able to reduce the experiment volume and to test the strength properties of an alloy with rhe nium and cobalt using its [111] single crystals.…”

“…Based on the studies of a γ'(Ni 3 Al) based VKNA 1V alloy [13], we decided to investigate only [001] and [111] single crystals, since [011] single crystals have lower strength and hot strength characteristics. To grow single crystals by high gradient directional solid ification (HGDS), we chose a temperature gradient G = 150°C/cm during solidification, which allowed us to form a more homogeneous structure than the struc ture that forms during HGDS at G = 60-80°C/cm.…”

“…The influence of a crystallographic orientation (CO) and the solidification parameters (solidification gradient and rate) on the structure and properties of alloys was studied earlier on an intermetallic Ni 3 Al based VKNA 1V alloy with low contents of refractory metals (Cr, Mo, W), which was made according to the process that ensures a uniform distribution of the alloy components in microvolumes in single crystal sam ples [13].…”