Improving mechanical properties for pure irons by local surface mechanical attrition treatment

ABSTRACT

After a short-time surface mechanical attrition treatment process, a planar uneven structure was obtained on the surface of irons. The yield strength of the sample subjected to surface mechanical attrition treatment for 60 s is almost twice than that of the annealed sample, but the ductility is still well retained. The good combination of strength and ductility is mainly due to the extra strain hardening and the coexistence of soft and hard phases. The extra strain hardening delays the annihilation of dislocations and reduces the plastic instability, while the hard phase in the planar uneven structure suppresses the crack initiation, and the soft phase delays the crack propagation.

KEYWORDS:

• Surface mechanical attrition treatment (SMAT)
• pure iron
• extra strain hardening
• soft and hard phases
• gradient structure layer

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was supported by National Nature Science Foundation of China [grant number 51374151], Key Scientific Research Project in Shanxi Province [grant number MC2016-06, 201603D111004 and 201805D121003], Research Project Supported by Shanxi Scholarship Council of China (2017-029), Patent Promotion and Implement Found of Shanxi Province [20171003].