Search results

The next step addition a properly measured amount of Terfenol-D powder with a grain size of 0-300μm (according to the manufacturer: Gansu Tianxing Rare Earth Functional Materials Co., Ltd.).
The shape and size of the grains is shown in Fig. 1.
Subsequent numbers in the graphs correspond to the following steps during the test: · 1 – start of the measurement and application of magnetic field, · 2 – loading of the actuator (load 20 kg) (blue dashed line), · 3 – unloading of the actuator (red dashed line).

As can be seen from Fig. 2, the sample with molten salt mainly consists of rod-like ZrSiO4 whiskers, while the sample without molten salt entirely composed of zircon grains.
When the temperature rises to 850 oC, the sample mainly consists of well-developed zircon whiskers with average diameter of ~100 nm and aspect ratio of more than 15, accompanied by a small number of zircon grains.

Seen from the SEM pictures, firstly, it is interesting to note that the films seem to be composed of densely packed spherical micro-sized clusters which were consists of number of spherical nanosized grains, of which the diameter is increased with the complexing agents from (I) to (III).
The clusters in ZnSe samples obtained from solution (I) are merged together to form the grain boundary like ceramics because of drying.

This result indicates that when the volume of N2H4 increases from 5mL to 10mL, the grain growth of thin film becomes easy, which results in Eg decrease.
However, when the volume of N2H4 increases to 15mL, the higher concentration of N2H4 increases the number of nucleation points on the substrate and decreases the single grain growth rate.

It is also confirmed by the grain size, which is 1.5 times larger in the large sample, and difference in the initial strength properties of the deformed samples.
Numbers on the plots show hardened material annealing temperatures in °C As the annealing temperature increases, the materials tend to gain plasticity and to naturally loose their strength.
This zone expands with grain size, but strength becomes lower.

It can be seen from the SEM that the existence of fully recrystalized grain boundary reduced the probability of intergranular fracture, and the cracks often expand along the interface of α/β phase, so the crack propagation path is devious and absorb more energy when fracturing ,thus, the fracture toughness increased[2].The acicular secondary α phase in β grain consist of lamellar structure, and there are a number of secondary α phase short acicular α phase formed in these parallel platelet structure.

Particle reinforced metal matrix composites have many good properties such as low cost enhanced body, uniform microstructure, isotropic material properties, good machining performance etc and hence draw much attention[4].A large number of domestic and foreign scholars’ experiments show that alloy’s properties can be improved and enhanced with the particles added[5-7].
The β phase can decompose into lamellar structure via β→α+η+ε, which was developed within the grain.
In addition, the β phase can transform into the irregularly cellular structure through discontinuous reaction, which was developed along the grain boundaries at the aging time.The granular α’ phase in the composites is fine with the size of less than 2 μm.The reason is that the α’ phase can’t grow adequately due to the rapid cooling rate of spray deposition.

There have been a number of studies on the effect of an electric current on the solidification and crystal growth of low melting point metals and alloys i.e.bismuth, cadmium, zinc, bismuth-tin alloys, aluminum and it’s alloys, lead-tin alloys etc [3-5].
It has been found that all the three samples have much thicker grain boundary near the cathode than that near the anode, which is mainly caused by the impurity aggregating towards grain boundary.

The grain size is about 3-4 µm for the AlN matrix, and 1-2 µm for the granular copper with a light color.
Sintering density of the AlN layer is higher than that of the AlN-20%Cu layer, and a larger grain size of about 3-7 µm are also formed, as shown in Fig. 3(c), because a higher sintering temperature was produced.
As shown in Fig. 3(e), the number of the observed pores is fewer than those at the TiB2-70% AlN layer, mainly because the sintering temperature is further elevated.

The REFO material exhibits large well defined grains, which are poorly linked to the surrounding material, as is shown on Fig. 1.
Low cohesion of large grains is a clear feature predominantly in the REFO material.
However further investigation considering a large number of thermal shock cycles is essential.