Formation of Nanocrystalline Structure in Steels by Air Blast Shot Peening

The formation of nanocrystalline structure (NS) on the surface of bulk steel samples by a particle impact and air blast shot peening techniques was studied. Nanocrystalline layers with several microns thick were successfully fabricated by these methods. The nanocrystalline layers produced in the present study have extremely high hardness and separated from adjacent deformed morphology region with sharp boundaries. By annealing, nanocrystalline layers showed slow grain growth without recrystallization. Those characteristics are similar to those observed in the NS produced by ball milling and a ball drop deformation. It was suggested that to produce NS by deformation a large strain is a necessary condition and a high strain rate and low temperature are favorable conditions.

[1]  K. Tsuchiya,et al.  Formation and annealing behavior of nanocrystalline ferrite in Fe-0.89C spheroidite steel produced by ball milling , 2002 .

[2]  R. Valiev,et al.  Structure and deformaton behaviour of Armco iron subjected to severe plastic deformation , 1996 .

[3]  Werner Österle,et al.  Investigation of white etching layers on rails by optical microscopy, electron microscopy, X-ray and synchrotron X-ray diffraction , 2001 .

[4]  D. Rigney,et al.  Orientation determination of subsurface cells generated by sliding , 1983 .

[5]  C. Koch,et al.  The hall-petch relationship in nanocrystalline iron produced by ball milling , 1990 .

[6]  J. D. Campbell,et al.  The temperature and strain-rate dependence of the shear strength of mild steel , 1970 .

[7]  K. Tsuchiya,et al.  Comparison of the Characteristics of Nanocrystalline Ferrite in Fe-0.89C Steels with Pearlite and Spheroidite Structure Produced by Ball Milling , 2002 .

[8]  Jian Lu,et al.  Surface nanocrystallization of iron induced by ultrasonic shot peening , 1999 .

[9]  K. Tsuchiya,et al.  Formation and Annealing Behavior of Nanocrystalline Steels Produced by Ball Drop Test , 2002 .

[10]  Gang Liu,et al.  Low carbon steel with nanostructured surface layer induced by high-energy shot peening , 2001 .

[11]  K. Tsuchiya,et al.  Formation mechanism and annealing behavior of nanocrystalline ferrite in pure Fe fabricated by ball milling , 2001 .

[12]  K. Tsuchiya,et al.  Nanostructured Fe-C alloys produced by ball milling , 2001 .

[13]  K. Tsuchiya,et al.  Formation of nanocrystalline structure in steels by ball drop test , 2002 .

[14]  W. Johnson,et al.  Nanocrystalline metals prepared by high-energy ball milling , 1990 .

[15]  J. Clark.  Response of Metals to High Velocity Deformation , 1960 .

[16]  N. Hansen,et al.  Graded nanostructures produced by sliding and exhibiting universal behavior. , 2001, Physical review letters.

[17]  Jian Lu,et al.  An investigation of surface nanocrystallization mechanism in Fe induced by surface mechanical attrition treatment , 2002 .