Incorporation of Y2O3 Particles into 410L Stainless Steel by a Powder Metallurgy Route

Addition of yttria to steels has been proposed for the fabrication of oxide-dispersion-strengthened materials for nuclear power applications. We have investigated materials prepared from 12 Cr martensitic stainless steel, AISI 410L, produced by powder metallurgy. Materials were produced with and without yttria addition, and two different sizes of yttria were used, 0.9 µm and 50 nm. Tensile and mini-creep tests were performed to determine mechanical properties. Optical microscopy, SEM, TEM, and EDX analysis were used to investigate the microstructures and deformation mechanisms and to obtain information about non-metallic inclusion particles. SiO2, MnS, and Y2Si2O7 inclusion particles were observed. An SiO2 and Y2O3 interaction was seen to have occurred during the ball milling, which impaired the final mechanical properties. Small-angle neutron scattering experiments showed that the matrix chemistry prevented effective dissolution of the yttria. © The Author(s) 201

Residual stress distributions in a P91 steel-pipe girth weld before and after post weld heat treatment

In this study the residual stresses in a pipe girth weld in a ferritic-martensitic power plant steel were measured by neutron diffraction and compared with the corresponding metallurgical zones in the weld region. It was found that, in both the as-welded and post-weld heat treated condition, the highest tensile stresses resided near the outer boundary of the heat-affected zone (HAZ), and towards the weld root region. Substantial tensile direct and hydrostatic stresses existed across the HAZ, including the fine-grained and intercritically annealed regions, where premature type IV creep failures manifest in 9–12 Cr steel welds. Compressive stresses were found in the weld metal coinciding with the last weld bead to be deposited. Constrained cooling tests on test coupons illustrated that these compressive stresses can be explained in terms of the influence that solid-state phase transformations have on the accumulation of stress in welds. (C) 2011 Elsevier B.V. All rights reserved

Genome Modification Approaches to Improve Performance, Quality, and Stress Tolerance of Important Mediterranean Fruit Species (Olea europaea L., Vitis vinifera L., and Quercus suber L.).

In the last decades the interest on traditional Mediterranean fruits highly increased, not only due to the constant demand of consumers for new crop alternatives, but also due to the identification in such species of molecules with important properties for human health (e.g. resveratrol from grapes and oleuropein from olives). Efforts to improve the production capacity and fruit quality in such fruit species, as well as the resistance to biotic and abiotic stress, was achieved by plant breeders using mainly classical breeding approaches (e.g. selection, hybridization and mutagenesis), nevertheless, breeding support by plant tissue culture techniques, marker assisted selection, as well as by genome modification, was also used. Here we will present the state of the art related with the production of transgenic plants in three Mediterranean fruit species with important impact on the economy, olive, grapevine and cork. The achievements, problems and future perspectives will be discussed.This work was financially supported by national funds through FCT (Foundation for Science and Technology) under the Project UID/AGR/00115/2013, PTDC/BIA-BQM/28539/2017, by the Project OLEAVALOR (ALT20-03-0145-FEDER000014) funded by FEDER funds through the Program Alentejo 2020; Hélia Cardoso and Susana Serrazina were supported by FCT through post-doc fellowship SFRH/BPD/109849/2015 and SFRH/BPD/108653/2015, respectively; Andreia Figueiredo was also supported by the investigator FCT program IF/00819/2015