Cyclic Deformation Behavior of Fe-18Cr-18Mn-0.63N Nickel-Free High-Nitrogen Austenitic Stainless Steel

  • PDF / 2,829,777 Bytes
  • 11 Pages / 593.972 x 792 pts Page_size
  • 64 Downloads / 212 Views

DOWNLOAD

REPORT


ODUCTION

HIGH-NITROGEN stainless steels have been widely used as structural materials nowadays for their excellent tensile strength, fatigue strength, fracture toughness, and corrosion resistance.[1] However, the high cost of nickel (Ni) has become a major obstacle in industrial production of Ni-bearing stainless steel. In addition, the release of trace Ni element will cause allergy in human bodies when these materials are used for biomedical purposes.[2] Therefore, Ni-free high-nitrogen austenitic stainless steel (henceforth called Ni-free HNASS) has been developed, and intensively investigated in recent years.[3–5] Our recent work demonstrated that the Nifree HNASS showed superior tensile strength (~1.0 GPa) with comparatively high elongation (30 to 40 pct) at various strain rates.[6] Recently, Maruyama et al.[7] also found that among traditional metallic biomaterials such as SUS316L (CR), Ti-6Al-4V alloy, C.W. SHAO, formerly Master Student with the Institute of Materials Physics and Chemistry, College of Sciences, Northeastern University, P.O. Box 104, Shenyang 110819, P.R. China, is now Ph.D. Student with the Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, P.R. China. F. SHI, Lecturer, is with the Institute of Materials Physics and Chemistry, College of Sciences, Northeastern University. X.W. LI, Professor, is with the Institute of Materials Physics and Chemistry, College of Sciences, Northeastern University, and also with the Key Laboratory for Anisotropy and Texture of Materials, Ministry of Education, Northeastern University, Shenyang 110819, P.R. China. Contact e-mail: [email protected] Manuscript submitted September 28, 2014. Article published online 29 January 2015 1610—VOLUME 46A, APRIL 2015

and Co-Cr alloy, HNASS displayed the highest fretting fatigue limit in air and in phosphate-buffered saline, which makes HNASS capable of utilization as a potential metallic biomaterial. A review on the development of Ni-free nitrogen-containing stainless steels for metallic biomaterials was once reported by Sumita et al.[8] Investigations on mechanical properties and corrosion resistance of Ni-free HNASS have been widely carried out.[9–11] However, few reports are available on its fatigue properties.[12] In fact, cyclic deformation behavior involving macro-mechanics and microstructures has been investigated for many years. The cyclic flow stress can be generally separated into two components, i.e., effective stress (rE) and back (or internal) stress (rI).[13] Effective stress comes from short-range interactions and represents the stress required to make dislocation overcome the resistance to its movement. The resistance includes periodic lattice resistance, phonon drag, restriction induced by other dislocations, and also the resistance due to the variation of short-rangeordering (SRO) interaction.[14] Back stress is associated with long-range interactions between dislocations and microstructural heterogeneities of materials, i.e., grains,