Fatigue crack growth characteristics of nitrogen-alloyed type 347 stainless steel under operating conditions of a pressurized water reactor
Abstract The fatigue crack growth behavior of Type 347 (S347) and Type 347N (S347N) stainless steel was evaluated under the operating conditions of a pressurized water reactor (PWR). These two materials showed different fatigue crack growth rates (FCGRs) according to the changes in dissolved oxygen content and frequency. Under the simulated PWR conditions for normal operation, the FCGR of S347N was lower than that of S347 and insensitive to the changes in PWR water conditions. The higher yield strength and better corrosion resistance of the nitrogen-alloyed Type 347 stainless steel might be a main cause of slower FCGR and more stable properties against changes in environmental conditions.
Corrosion fatigue crack growth behavior of 316NG heat affected zone in simulated pressurized water reactor environment
Abstract The corrosion fatigue crack growth (FCG) behavior of the 316NG heat affected zone (HAZ) exposed to simulated pressurized water reactor (PWR) environment has been investigated. The results show that significant residual strains and lattice misorientations exist in the HAZ near the welding root. Z-phase precipitates are present in both the HAZ and annealed 316NG base metal. The FCG rate of the HAZ is much higher than that of the base metal. In PWR water, the corrosion FCG rate of the HAZ is strongly dependent on the cyclic loading frequency, but the effect of dissolved oxygen is negligible.
Chapter 1 – Nanotechnology: A Toolkit for Cell Behavior
Tissue engineering seeks to effectively manipulate cellular populations to improve the function of damaged or diseased tissues and organs. Many techniques can affect cell behavior; however, in order to maintain desirable function, scientists and engineers design solutions that are as biomimetic as possible. True biomimeticity is very challenging without the incorporation of nanotechnology. Since cells in human tissues are surrounded by a 3D hierarchical tissue extracellular matrix containing numerous nano components, a revolutionary change in tissue engineering is to explore biomimetic nanobiomaterials and advanced 3D nano/microfabrication techniques for creating novel tissue constructs and regulating cell behavior. This chapter will provide an overview of recent nanotechnology in tissue engineering applications. We will put special emphasis on integrating cutting-edge 3D nano/microfabrication techniques with nanobiomaterials for complex tissue and organ regeneration.