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Introduction The microstructure in 6000 series alloys can be described in terms of grain structure (size, shape, texture), intermetallic phases, precipitates and the matrix; all of which are determined by the alloy content and production processing route.
Although the number of intermetallics identified is small (total 50 particles), the results show a consistent trend for the intermetallics to have a decreasing ratio of Fe:Si (from α → β → π) with increasing alloy Si content. 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1 3 5 7 9 11 13 15 17 19 Microprobe line trace (pos.)
Table 3: Combined TEM and SEM results for number and type of Fe-intermetallics, in order of alloy Si (*no data on alloy L5).
Further SEM-EDS work was undertaken to increase the number of intermetallic particles measured for alloys L1, L4 & L7 in T4 heat-treated extrusions.

All such aspects of this approach are being pursued in the IMPRESS (Intermetallic Materials Processing in Relation to Earth and Space Solidification) research project, which has a number of scientific and technical objectives that will lead to the creation of advanced prototypes for extreme applications.
One of the main scientific objectives of the IMPRESS project is quantitative determination and understanding of the fundamental mechanisms that control growth and evolution of grains, including the columnar to equiaxed transition (CET), during solidification of γ-TiAl intermetallic alloys.
However, once validated and/or verified, the approach developed in this work is generally applicable to a number of solidification processes and furnaces. 0 100 200 300 Time [s] 0 0.002 0.004 0.006 0.008 0.01 0.012 Tip velocity [cm/s] 0 10 20 30 Gradient at the tip [K/cm] Tip velocity [cm/s] Gradient at the tip [K/cm] Cooling rate = 0.32 [K/s] - upper surface Cooling rate = 0.12 [K/s] - upper surface 0 100 200 300 Time [s] 0 1 2 3 4 Dendrite tip undercooling [K] 0 1 2 3 4 Equiaxed Index, Ieq [Kcm-2] Dendrite tip undercooling [K] Equiaxed Index, [Kcm-2] Fig. 6.
FTM numerical simulation: a) a dendritic tip velocity and gradient at the tip; b) an equiaxed index and dendrite tip undercooling Acknowledgements This work has been supported by the IMPRESS Integrated Project in the 6th Framework Programme co-funded by the European Commission (contract number NMP-CT-2004-500635) and the European Space Agency.

The SLM process enables the direct melting of powders of a number of metals, such as titanium, steel, chrome cobalt, aluminum alloys, and building of parts through a “layer by layer” approach.
Cold-finishing is necessary as to not temper or work harden the surface during preparation. [10] Micro Hardness Measuring The micro hardness is measured using the Micro hardness tester FM 700, a device that can measure the HV hardness on micrometric surfaces (on the grain level) on metals and nonmetals using load forces between 1- 1000 [gf].
To obtain a Vickers hardness number, HV, that is an expression of hardness, the applied force is divided to a Vickers indenter by the surface area of the permanent indentation made by the indenter.
The Vickers hardness number, in terms of [gf] and [μm], is calculated as follows [11]: HV=1854.4×Pd2, (2) where: P is force in [gf] and d is mean diagonal length of the indentation, [μm] (Fig.10.)

It was reported that for an operation of 400,000 km/year the number of stress cycles of axles and wheels is about 2x108 cycles [1] falling in the fatigue life known as gigacycle fatigue [2].
A number of 100 measurements of splats diameter and thickness were performed for each sample in order to evaluate the splats average size and distribution.
These findings are consistent with other author’s works that have studied the influence of the support material temperature on the splashing tendency and grain morphology [11].
A number of 100 splats randomly selected on the top surface were measured and the distribution and average equivalent splat diameter, D, was calculated.

Then, all the substrates were grit blasted by alumina powder with 80 mesh grain size distribution.
Temperature range preoxidation dwelling Phase angles Strain range lifetime* TMF 1 900~200oC 1000oC/100h 5min OP -0.30% 65 2 900~200oC 1000oC/100h 5min OP -0.45% 5 TGMF 3 1000~300oC 1000oC/100h 5min OP -0.30% 692 4 1000~300oC 1000oC/100h 5min OP -0.45% 37 5 1000~300oC - 5min OP -0.45% 340 6 1000~300oC - - OP -0.45% 1500 *The lifetime means the number of cycles when TBCs spallation occurred Results and Discussion Fig. 3 TMF/TGMF lifetime of TBC systems.
TBC spallation occurred after various numbers of cycles and the TMF/TGMF lifetime (It means the number of cycles when TBCs spallation occurred rather than the rupture of the sample) is drawn in Fig. 3.

When studying the multifactor dependencies with optimization of composite materials com-positions, the number of experiments can be reduced as a result of the experiment mathematical planning [11, 12].
When performing the research by using the conventional methods, the composition and processing factors optimization is associated with a large number of experiments.
Experimental planning methods make it possible to theoretically determine the minimum number and procedure of experiments to obtain a mathematical model.
Balykov, Experimental and statistical models of the properties of modified dispersed reinforced fine grained concrete, Magazine of Civil Engineering. 2(62) (2016) 13-26 (Russian)

Deformation introduces a large density of dislocations into the material, which can alter the precipitation behaviour and sequence in a number of ways [1-5]: (i) Dislocations act as vacancy sinks and annihilate quenched-in vacancies resulting in the suppression of clustering during natural aging [1, 6]; (ii) Dislocations provides heterogeneous nucleation sites for precipitates [5]; (iii) Precipitation on dislocations promotes the stable rather than metastable phases [1]; (iv).In many alloys the presence of dislocations prior to aging may increase mechanical properties after the heat treatment, which results from the superposition of the modification of the precipitation characteristics and of the intrinsic strain hardening due to dislocations.
New dislocations are then generated or multiplied as proposed by the Frank-Read mechanism [17], and they further frequently pile up on slip planes at grain and subgrain boundaries.
The governing factor for such a case is the dislocation density, when with increasing amount of introduced dislocations, the number of nucleation sites for precipitates is increased and faster dislocation-assisted diffusion replaces slower bulk diffusion.
These observations are in a good agreement with the findings of a number of research groups [2, 4, 7, 19, 20].

Regarding the fatigue tests, this study uses a standard theoretical model to derive curves of amplitude stress versus number of cycles for the current nanotubes.
Regarding the fatigue test, this study uses a standard theoretical model to derive curves of amplitude stress versus number of cycles for the current nanotubes.
(C) Cyclic stress versus number of cycles to failure for a representative GaNNT with various temperatures. 3.4 Mechanical characteristics of carbon nanotube (CNT) junction.
Chiang, Effects of grain size and orientation on mechanical and tribological characterizations of nanocrystalline nickel films, Wear 303 (2013) 262-268 [6] P.C.

Introduction Positron annihilation lifetime spectroscopy (PALS) is very sensitive and able to identify different kinds of defects and their agglomerates such as vacancies, dislocations, vacancy loops, grain boundaries, vacancy-impurity complexes, and voids [1-4].
A consequence of the absorption by MR is the considerable decrease in positron intensity and hence the number of annihilation incidences is lower in the composite.
The positronium lifetime tPs also showed a decrease at higher irradiation doses since the number of smaller pores increase as the aggregated vacancy clusters initially form small pores.
In this scenario, one expects a decrease in Ie+ with a corresponding increase in IPs as the aggregated vacancy clusters form small pores resulting in an increase in number of pores as the irradiation dose increases.

Introduction Oxynitride glasses exist as grain boundary phases in silicon nitride ceramics.
In order to improve creep and other properties of silicon nitride ceramics and to understand the nature of the oxynitride glasses containing different rare-earth elements, which are used as sintering additives in silicon nitride ceramics, a number of investigations on bulk oxynitride glass structure and properties have been undertaken over the last two decades.
The number of tests for each glass depended on the number of available samples.