Search results

Material Processing and Experiments High purity Al2O3 powder with grain size of 0.2 µm and titanium carbonitride (TiC0.5N0.5) powder with size of 0.1 µm were used as starting materials.
The formula for calculating the toughness from SENB geometry can be found in a number of texts and handbooks [e.g. 8], and can be expressed as () aY BW PS KIC ⋅⋅= α2 2 3 (1) where P is the failure load, S is the span, B is specimen thickness, and Y(α) is geometry factor that is dependent on both α-ratio and span-to-depth ratio, S/W, and is often written as () 4 4 3 3 2 210 αααα α AAAAAY ++++= (2) in which, constants A0 to A4 vary with S/W ratio.
The changes of (a) Vickers hardness, (b) bending strength, (c) fracture toughness with sintering temperature for Al2O3/Ti(C,N) composites with 10, 20, 30, and 40 wt%Ti(C,N) decreasing grain size because of the restraint of Ti(C,N) particles along the Al2O3 boundaries on grain growth.
It can be seen here that the increase of sintering temperature from 1650 to 1750 °C has led to about five folds increase in grain size as well as dramatically increased porosity.
It has been demonstrated that such behaviours of Al2O3/Ti(C,N) composites are in fact, a combined result of the limitation of Ti(C,N) phase on the growth of Al2O3 grain and the decomposition of Ti(C,N) phase itself.

In general, the number of constitutents (Xi) in the HEA is increased to maximize the entropy of mixing (ΔS).
Microstructure, Mechanical and Thermal Properties Major mechanisms responsible for the ultrahigh strength of the HEA based composites are solid solution strengthening, grain boundary strengthening, dislocation strengthening and deformation induced nano-twinning.
The addition of nano-particles has reduced the grain sizes of CoCrFeMnNi HEA matrix from 168 nm to 108 nm by grain pinning mechanism, as shown in Fig. 2[11].
The grain refinement enhanced the strength from.
The twins create interfaces inside the grain.

The number of replications of each condition was five, and a spacing distance between consecutive tracks was kept at 0.5 mm.
Upon cooling, the grains formed fine lath martensite (FLM), leading to elevated hardness slightly lower than in the MZ.
The finer grain size in the HZ is due to thermal gradients limiting grain growth.
This can thereby lead to grain growth and hardness reduction.
This is plausibly owing to the heat accumulation that retards the cooling rate and prevents the laser heated region to form fine grains of hardened structures.

The new weld structure in general would include a HAZ containing recrystallised, equiaxed grains and some heavily worked grains at the weld interface.
However, this is an oversimplification, as when welding steels, especially alloys, it would be expected that in addition to changes in grain size and shape the extremely rapid cooling rates that occur would create transformation products within the weld.
Higher speeds tend to increase the width of the HAZ and also the grain size.
Subsequent use of high pressure forging after spindle stop is used to work the structure and refine the grain size.
From this it is clear that the component failed well within the SCMV side of the weld and also that the failure point was at the limit of the HAZ, which is shown by the dark band at 1.3-1.8mm into the SCMV side of the weld, Figure 1, and also that the HAZ in the SCMV material has the lowest hardness number of the weld.

Moreover, the size of primary α-Al grains decreases obviously compared with Fig. 2(a).
This is due to nano-SiCp are almost rejected by solid/liquid interface during the solidification and distributed at the boundaries of primary α-Al grains, which can also hinder the growth of α-Al grains.
So, the size of primary α-Al grains decreases obviously and the number of α-Al grains increase.

The images (Figure 8 a) showed some twinning within the mainly alpha grains (d = (30 to 80) µm) indicative of hydride formation.
The formations shown from another area (Figure 8 b) are the alpha grains with contamination likely from the trace carbon identified from EDS.
German, R., Coarsening in Sintering: Grain Shape Distribution, Grain Size Distribution, and Grain Growth Kinetics in Solid-Pore Systems.
Leme, F.O., et al., Effect of pulse repetition rate and number of pulses in the analysis of polypropylene and high density polyethylene by nanosecond infrared laser induced breakdown spectroscopy.

As shown in the micrograph of Figure 1b, powders are composed mainly of spherical and some odd shaped particles with a high number of satellites sticking on their surface.
As it is evident from the rightmost end of the image, large columnar grains of 316L grow from the start plate (also made from a stainless steel grade 304).
As the material grows (from right to left in Figure 3a), carbides start to precipitate and coexist within 316L grains in a narrow region until the columnar configuration is broken and the size of the grains is drastically reduced.
Small grain microstructures have been reported earlier for V4E materials due to the nucleation effect of carbide precipitates [8].
Pure V4E microstructure is configured of very fine grains and V- and Mo- carbides.

., melt number HX-032, chemical composition and mechanical properties, as stated in the material sheet, are given in Table 1.
Results and Discussion The microstructure of the Ti6Al4V alloy in the initial state consists of a lamellar α-phase deposited in the polyhedral grains of the original β-phase.
The β-phase polyhedral grains are deformed, stretched in the hot rolling direction with an average length of 479 µm and a width of 159 µm (Fig. 1a).
The grain of the basic β-phase has grown significantly, the microstructure is formed by grains of different sizes and in the case of a higher cooling rate (WQ, AC – Fig. 1c, d) the α-phase was transformed into Widmanstätten needles (in the case of AC) or martensitic α¢-phase with needle morphology (in the case of WQ).
The microstructure of the alloy was transformed by the applied heat treatment, where the grains of the original β-phase grew and, depending on the cooling rate, the α-phase recrystallized from the original lamellar form to Widmanstätten needles or a martensitic α¢-phase.

Monte Carlo method is a statistical simulation method depending on random numbers.
Comparisons show that GPU can achieve an extreme speedup over CPU, and the hybrid mode of coarse-grain parallel computing among GPUs and fine-grain parallel computing within GPUs can get nearly linear speedup.
With continuously increased number of cores in combination with a high memory bandwidth, a recent GPU can offer incredible computing power.

To reduce expenses, the number of wind and waves trials was reduced to minimum.
According to the actual development, the PLC internal parameter table (part) is made as follows: l 2FPLC 32CCL set the station number (StationN0 :) 13 ~ 16 occupies 4 stations; l Master station RWr (from the slave station to the main station) address range: 310H3 ~ 1FH total of I6 points; l Master station RWw (from the main station to slave station) address range: 210H ~ 21FH total of l6 points; l Master station RX (from the slave station to the main station) address range: F8H ~ FFH A total of 112 points; l Master station RY (from the main station to slave station) address range: I78H ~ 17FH a total of 112 points.
“Analysis and Modeling of the Central Air-Condition in System in” [4] Zhou Jinzhu, Yan Qinlao, Fan Fangjuan, “The design of grain depot grain situation wireless supervisory control based on GPRS”.