INVESTIGATION OF THE QUALITY OF EXPERIMENTAL HEAT-RESISTANT RHENIUM-FREE ALLOY ZMI-M5 (ZHS32B-VI)

2018

Авіаційно-космічна техніка та технологія, Vol 0, Iss 7, Pp 88-94 (2018)

One of the features of the operation of ground installations in contrast to aircraft engines is the much lower quality of the fuel used. As a result, the combustible materials used contain much more aggressive (sulfur and other) contaminants, which leads to the non-strength characteristics of the material of cast parts of the hot tract, and their ability to resist high-temperature corrosion in the operating conditions of the unit. Analysis of the effect of alloying elements on the properties of high-temperature nickel alloys for ground installations leads to the conclusion that it is expedient to completely eliminate expensive rhenium from their composition and replace it with an increased content of relatively less expensive alloying elements, which simultaneously provide sufficiently high heat resistance and necessary resistance against high-temperature corrosion. The composition, structure and properties of cast samples obtained from the experimental heat-resistant rhenium-free alloy ZMI-M5 (ZhS32B-VI), by high-speed directional crystallization were studied. The alloy ZMI-M5 (ZhS32B-VI) according to the content of elements (with the exception of tungsten content) complies with the requirements of the temporary technical conditions. Mechanical properties, as well as long-term strength at the 975 ºC test temperature and 30 kgf/mm2 loading meet the requirements of the temporary technical conditions. The time to failure at a temperature of 1000 ºC under a load of 28 kgf/mm2 is unstable, ranging from 21 to 55 hours. The decrease in the tр values at 1000 ºC is probably due to the crystallographic direction of the samples. It is established that higher tр values (55 h) have samples with a crystallographic orientation. The microstructure of the samples after heat treatment is characteristic of high-temperature nickel alloys of the ZhS type. Heat treatment in this regime did not lead to a significant eutectic (γ-γ) phase reduction in the metal. The experimental alloy ZMI-M5 (ZhS32B-VI) does not contain rhenium, it has a significantly lower cost, while it provides mechanical properties at the level of the industrial alloy ZhS32-VI and can be used for ground use gas turbine installations blades manufacturing by directional crystallization.

article

English
Ukrainian

National Aerospace University «Kharkiv Aviation Institute», 2018.

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