Effect of Annealing Temperature on Microstructure and Mechanical Properties of Bulk 316L Stainless Steel with Nano- and
- PDF / 11,998,181 Bytes
- 9 Pages / 593.972 x 792 pts Page_size
- 97 Downloads / 228 Views
I.
INTRODUCTION
AUSTENITIC stainless steels are widely used because of the combination of good strength and corrosion resistance, and their annual global production is about 50 million tons nowadays.[1] Owing to potential large decrease of raw material and energy consumption in using, stainless steels with higher strength and wear resistance are hot concerned. Among the steels strengthening mechanisms, grain refining is an important and promising way. In the last two decades, it was exhibited that nanocrystalline steels have a very high strength up to 2 GPa, which is attributed to few dislocation existence in the nanocrystalline grains, and a large number of disordered atoms at the grains boundaries. However, low tensile ductility and plastic instability are also found in the nanocrystalline steels, which seriously hinder their potential wide structural applications.[2–8] The low tensile ductility comes from their very poor work hardening capacity resulted by their inability to accumulate dislocations owing to absence of dislocations and very high stress to onset dislocations sources to produce the dislocations and dislocations sliding in the nanocrystalline grains.[6–8] Recently, it is found that existence of some amount of grains in micrometer in the nanocrystalline grains matrix can improve the ductility a lot without much loss of the strength, and the microand nano-crystalline dual-phase can provide a good PEIQING LA, Professor, FUAN WEI, XUEFENG LU, and HONGDING WANG, Researchers, CHENGGANG CHU and YUPENG WEI, Lecturers, are with the State Key Laboratory of Gansu Advanced Non-ferrous Materials, Lanzhou University of Technology, Lan Gongping Road 287, Lanzhou 730050, Gansu, P.R. China. Contact e-mail: [email protected] Manuscript submitted August 18, 2013. Article published online July 12, 2014 5236—VOLUME 45A, OCTOBER 2014
compromise between high strength and considerable tensile ductility.[9–14] Several methods such as nanopowders consolidation and severe plastic deformation (SPD) are successfully developed to prepare steels with the micro- and nanocrystalline dual-phase.[1–14] But the available methods are complicated and difficult to scale up for industrialization. New fabrication methods to prepare the micro- and nano-crystalline dual-phase steels with both high strength and considerable tensile ductility and potential to scale up for industrialization are heavily pursued now.[1–14] Aluminothermic reaction casting is a new method to prepare nanostructured alloys.[15–22] The process is simple, low cost, and energy consumption and can be easily scaled up. Thus, its industrialization is possible. In this paper, 316L stainless steel with nano- and micro-crystalline dual-phase and high strength and considerable tensile ductility is prepared by the aluminothermic reaction casting and a followed annealing. Microstructure and mechanical properties of the steel, as well as the microstructure formation and mechanical properties enhancing mechanisms, are explored.
II.
EXPERIMENTS
Commercial ferric oxide and aluminum powde
Data Loading...
