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Lower structural perfection of W‐Ta single crystals is associated with considerable disturbance of the melt by plasma arc, great temperature gradients and cooling rate of the growing single crystal due to “air rinsing” of its surface by plasma‐forming gas. In the peripheral areas of this sample a large number of small sub‐grains is presented, which confirms the trend towards fragmentation of the structure at crystallization from the beginning to the end of the ingot.

Manufacturing features, structure and properties of low-alloyed molybdenum sheets 0.5 mm thick made from the experimental Mo-3 wt.% Re single crystal are described and discussed in the present work. The developed technological scheme includes warm rolling of the initial ingot at a temperature of 1150 °C, with heating in the argon protective atmosphere, subsequent annealing at 850 °C for 2/3 h in a vacuum, no less than 1 ·103 mmHg, cold rolling at a temperature of 400 °C, and post-deformation annealing at 800 C for 1/2 h. The results of micro structure analysis, physical and mechanical studies show that thin sheets are characterized by simultaneously high strength and plasticity, as well as the required temperature coefficient of linear expansion (TCLE), necessary for bonding with a glass by a thermo-compression welding. Obtained results reveal perspectives for the development of the application of thin Mo-3 wt.% Re sheets in vacuum engineering for the vacuum-tight metal-glass parts.