Mechanical Strength of Materials

Generating duplex microstructures by nitriding; nitriding of iron based Fe–Mn alloy

“…Nucleation barriers are smaller at grain boundaries, as grain boundary energy gets released upon nucleation. 33 Moreover, segregation at grain boundaries of possibly Mn may promote first development of austenite there too (Mn is an austenite stabilising element 34 ). As a next stage, and accompanied by a continuous increase in the N content, austenite develops also within the ferrite matrix grains [region (ii)], in association with dissolution of the Mn nitrides, developed before, leading to a completely austenitic region [at the nitriding temperature; region (i)].…”

A comprehensive review of synthesis kinetics and formation mechanism of geopolymers

“…71 The use of highly reactive silica increased the gel formation and compressive strength of geopolymer. 115 The Si/Al ratio of the specimen can be used to predict the resonance position and shape of geopolymers using 29 Si MAS NMR. 116,117 The Si/Al ratio depends on the raw materials composition, and it should be kept above the Si/Al ratio of the raw material to produce a higher compressive strength geopolymer.…”

“…27,28 The understanding of synthesis kinetics is very important for designing of new materials and the optimization of existing materials as it controls the microstructure and properties of the product materials. 29 In the rst two decades of the 21st century, research on geopolymer early age kinetics started to develop an understanding of the chemical reactions occurring during geopolymerization and the mechanisms involved in the formation of geopolymers. Few review papers on geopolymers such as mechanisms of geopolymerization and the factors affecting its development, 13 the structure and properties of clay based cements, 30 methods to evaluate and quantify the geopolymerization reactivity of waste-derived aluminosilicate precursor in alkali-activated material: a state of the art review, 31 phosphate-based geopolymers: a critical review 32 and on the advances in the synthesis and applications of geopolymers have been published.…”

Creep rupture properties of bare and coated polycrystalline nickel-based superalloy Rene®80

“…By consideration of the crystal properties of the present phases in the coatings, elastic strain of (6µm Pt/LTHA) and (6µm Pt/HTLA) specimens were reached as 1.5 ×10 -3 and 1.9 ×10 -3 , respectively (with the help of X'pert high-score plus software and utilize of stress-less sample of Yttrium oxide). Regarding coating elastic modulus 99 and 93 GPa for LTHA and HTLA, respectively [21] and the application of Hook's Law (σ = EƐ) [23], the value of the residual stresses were calculated as 148.2 MPa for LTHA and 176.7 MPa for HTLA, respectively. As seen, the value of residual stress in HTLA method is greater than LTHA, indicating another reason for the reduction in the rupture life in HTLA.…”