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Hence, new phases and different grain size result in the welding bead.
Laser welding is being increasingly considered to produce them because a number of benefits are provided in comparison with conventional technologies of fusion joining, since the heat source is narrowly focused to a very small area [1], in the order of few tenths of millimetres, depending on the beam quality.
Indeed, any welding thermal cycle, with rapid heating and cooling, results in changes in the base material; therefore, different properties and micro structures are expected across the welding zone and a number of distinct regions are identified.
Fig. 5: Fracture location in a hybrid Haynes 188 + Inconel 718 butt welded sample; Haynes on the left, Inconel on the right Base elements are generally nickel and cobalt, while property enhancement is achieved by the addition of aluminum, chromium, iron, molybdenum, titanium and tungsten, which segregate to the grain boundaries or lead to precipitation of a finely dispersed hardening phase in the base matrix; as a consequence, the material is significantly improved in strength [16].
An increasing trend is noticed at the Haynes side towards the fused zone; in particular, a 330 HV0.2 peak was achieved at the boundary of the fused zone, where peculiar grain morphology are pointed out via metallographic analyses.

The results showed that graphene can significantly improve the mechanical properties of composites and refine the matrix grain.
These existing groups, on one hand, make graphene evenly dispersed in the solvent, and on the other hand, destroy the sp2 hybrid structure of graphene, resulting in the appearance of a large number of structure defects, and the defects cannot completely eliminated by annealing at 1000 ºC.
Compared with general reinforcement, uniformly distributed graphene can refine matrix grain and pin dislocation.
It is obvious that the black area is graphene, which uniformly dispersed in the grain boundary.
Grain refinement: a mechanism for graphene nano-platelets to reduce fraction and wear of Ni3Al matrix self-lubricating composites [J].

Refining the β grain size of Ti-15-3 alloy can improve its ductility, but has minor effect on the tensile strength [5].
Coarse β grain size leads to a decrease in notched tensile strength (NTS) of the Ti-15-3 alloy [5].
The direct or one-step aged specimen was identified by designation of three-digit numbers prefixed with a capital letter A in reference to the aging temperature.
Results and discussion The microstructures of the Ti-15-3 alloy in the solution-annealed condition consisted of equiaxed β grains without any observable precipitates.
Furthermore, inter-granular fracture and grain boundary shear were observed in the D648 specimen.

And the problem is likely to get worse for the detection of micro-cracks located in the lower part or on the inner-surface of high thick-walled members or coarse-grained materials.
TOFD inspection procedures of high wall-thickness or coarse-grained members According to theoretical analysis and experiment results, a testing technique is made for the inspection of high wall-thickness or coarse-grained members.
The process code applies to the inspection of thick-walled metal parts with thickness of 50~200mm or coarse-grained metal members with thickness of 40~100mm.
An adequate number of flaws such as slots which can give strong diffraction signals should be used in blocks to ensure detect ability for the entire weld volume.

To reduce the number of samples considering the relatively high cost for each sample, Taguchi method with fractional factorial design was used (as stated in Table 1).
The corresponding microstructures of the evaluated areas are displayed in Fig. 5, with the corresponding grain sizes in longitudinal and transversal directions are displayed in Fig. 6.
It was contrary to the expectation that some microstructural changes should occur as in cold rolled samples, in which the grain length in transversal direction is much higher than that in longitudinal direction.
This absence of such change was due to the microstructures of the annealed samples were readily a relieved one (equiaxial grains).
Grain size of the initial sheet metal and of the cold spinned samples (in µm)

At present, the lighting lamps and lanterns of public buildings are mostly uses the manual switch, the failure rate is high, only suitable for incandescent lamp, not suitable for the use of LED lights and other lighting, here we introduce a set of AC power directly based on sensor, microcontroller ARM drive LED lighting system design The working principle of AC LED light source The working principle of AC LED light source as shown in figure 1, will be some LED matrix arrangement of tiny grain the staggered process is divided into four series, AC LED grain series composition, similar to a rectifier bridge rectifier bridge at both ends of the connecting AC power respectively, the other on both ends of the connection LED grain, solid arrows indicate the positive half cycle of communication with the current flow direction, two series of LED light-emitting grains, the negative half cycle with the dashed arrow direction of current flow, and there were 2 series of LED crystal light; Take turns
Infrared detector The detector has three key components: the Fresnel optical filter, it by the end of the wavelength of 8 ~ 12 um filter chip, a band-pass filter, interference environment by obvious control; Fresnel lens focusing effect, the pyroelectric infrared signal refraction (reflection) on the pyroelectric infrared sensor, the second role is alert zone can be divided into a number of bright and dark areas, Make alert in the moving object can be in the form of temperature changes on the pyroelectric infrared sensor changes the pyroelectric infrared signal, so that pyroelectric infrared sensor can produce changes in the electrical signals, Pyroelectric infrared sensor chip to filter through the light of the change of the infrared radiation energy is converted into electrical signals, and complete the thermoelectric conversion in curing system software processing the data collected in the operation, the control system in the control software through the control logic to decide whether

The range of primary α grain sizes is from 5 to 16 μm, and the average size is 10 μm.
High magnification photos around the fracture origins are shown in Fig. 7 (a) to (d), where the fatigue crack propagation is strongly affected by microstructure such as grains or grain boundaries around the crack tip.
In the unloaded part, 10 μm size of ferrite and pearlite grains were observed.
Acknowledgment This work was supported by JSPS KAKENHI Grant Number 23760081, Grant-in-Aid for Young Scientists (B).

There are a number of reports on the Nd2Fe14B/α-Fe two-phase system.
To obtain a sufficiently strong exchange coupling within the two-phase system, the grain size of the soft must be smaller than 2bcs, where bcs is the exchange length of the soft phase.
Usually the grain size is in the order of 10 nm [11].
Since it is very difficult to control the grain size below this value by traditional manufacturing process, in this work iron nanoparticles in size of 50 nm were used as soft phase source and subsequent high energy ball milling were applied to produce the two-phase system and reduce the grain size.

The 718Plus microstructure consists of a g matrix with a large number of phases: ordered face centred cubic g'-Ni3(Al,Ti) type phase, some orthorhombic d-Ni3Nb and hexagonal h-Ni3Ti, h*-Ni6AlNb or Ni6(Al,Ti)Nb particles precipitated at the grain boundaries and as a plate-late precipitates inside the grains [8].
This phase was precipitated as large particles usually associated with the M23C6 precipitates at the prior austenite grain boundaries.
Another factor influencing on the differences in contrast between grains with different crystallographic orientation is result of the occurrence of the channeling effect.

Currently, it is considered as the cause of early deterioration of an increasing number of concrete structures in Portugal.
In fact, when quartz grains are placed in the concrete interstitial solution, the attack by alkalis occurs mainly on its surface.
The same behavior is observed for large grains of quartz that have defects or are deformed.
This test consists on evaluating the behavior of an aggregate after being crushed to a grain size less than 4.75 mm, used for making mortar prismatic specimens with dimensions 2.5 cm x 2.5 cm x 28.5 cm.
Aggregate Petrographic analysis Mortar Concrete Reactivity Forms of reactive silica ASTM C 1260 (80º C) Reactivity Slow-test (38º C) Accelerated-test (60º C) Reactivity Expansion (%) Expansion (%) Expansion (%) 14 days 28 day 3 months 6 months 3 months 5 months Reactive aggregate (RA) R crypt. qz 0,30 0,51 R Ongoing test Ongoing test - Nonreactive aggregate (NR) NR - 0,00 0,00 NR - Granite A PR microcryst. qz 0,03 0,05 NR 0,00 0,01 -0,01 0,01 NR Granite B R crypt. qz 0,02 0,03 NR 0,00 0,00 0,05 0,07 R Dolomite PR str qz 0,02 0,03 NR 0,01 0,02 0,02 0,02 R Notation: crypt. qz– cryptocrystalline quartz; str qz– strained quartz; R – Reactive; PR – Potentially reactive; NR – Nonreactive The reactivity of the RA reference aggregate was confirmed by petrographic analysis, due to strong presence of quartzite (crystalline quartz), mylonites (stretched quartz) and chert (cryptocrystalline quartz) grains, well known alkali-reactive forms of silica (Fig. 1).