"Nanocomposites and nanomaterials"

The formation nanostructure in carbon steel 45
Makruha T.O. 
Admiral Makarov National University of Shipbuilding
Prospect Heroiv Ukrainy, 9, Mykolaiv-54025, Ukraine. 
E-mail: tmakruha@gmail.com

The actual task of modern material science is creating new nanomaterials with unique physical and mechanical properties.  New method of receiving new materials was developed by collective of the Department of Materials Science and Technology of Metals of National University of Shipbuilding. It is previous deformation and next pre-recrystallization heat treatment. This method allows increasing the hardness on 30…70 % [1].
The carbon steel 45 was investigated. It was conducted the combined deformation on 60 % and pre-recrystallization heat treatment about 500 °C [2].
The hardness after annealing was 1,7 GPa, after deformation – 2,47 GPa.
The properties of materials depend on size of nanostructure elements, such as size and quantity of coherent scattering regions (CSR) and angles of orientation subgrains.
Table 1 shows the results of determining sizes of substructure elements of carbon steel 45 after deformation and pre-recrystallization heat treatment.
The mode of deformation-thermal treatment	The hardness, GPa	Size of CSR, nm	Quantity of CSR, %	Angle of orientation, °	
60 %	2.24	116	15	0,44	
60 % + 500 °С, 2 min	2,55	80	20	0,88	
The influence of hardness after deformation and pre-recrystallization heat treatment is provided by decreasing of size of coherent scattering regions and increasing of quantity of coherent scattering regions and angle of orientation of subgrains. 
1.	Dubovyi O.M.,  Kulik S.H., Zhdanov O.O., Bobrov M.M.,  Myrko O.I. Effect of deformation and alloying elements on the hardness of steel and sprayed coatings after pre-recrystallization heat treatment // Collection of scientific papers of NUOS – 2011. – 2. – P. 36-44
2.	Dubovyi O.M., Lyu Shen, Makruha T.O. Influence of the combined deformation on the thermal stability of the poligonazation substructure of iron, nickel and steel 20$ 45 // Collection of scientific papers of NUOS – 2017. – 1. – P. 39-47