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In this study, changes in the microstructure, mechanical properties, and electrical conductivity of cast and extruded Al–Zn–Cu–Mg based alloys with the addition of Li (0, 0.5 and 1.0 wt.%) were investigated. The Al–Zn–Cu–Mg–xLi alloys were cast and homogenized at 570 °C for 4 hours. The billets were hot extruded into rod that were 12 mm in diameter with a reduction ratio of 38:1 at 550 °C. As the amount of Li added increased from 0 to 1.0 wt.%, the average grain size of the extruded Al alloy increased from 259.2 to 383.0 µm, and the high-angle grain boundaries (HGBs) fraction decreased from 64.0 to 52.1%. As the Li content increased from 0 to 1.0 wt.%, the elongation was not significantly different from 27.8 to 27.4% and the ultimate tensile strength (UTS) was improved from 146.7 to 160.6 MPa. As Li was added, spherical particles bonded to each other, forming an irregular particles. It is thought that these irregular particles contribute to the strength improvement.

In this study, microstructure and sintering behaviors of the gas-atomized Al-(25 or 30) Cr–xSi alloy (x = 5, 10 and 20 at.%) during spark plasma sintering (SPS) process were investigated. Gas-atomized alloy powders were manufactured using Ar gas atomizer process. These alloy powders were consolidated using SPS process at different temperature under pressure 60 MPa in vacuum. Microstructures of the gas-atomized powders and sintered alloys were analyzed using scanning electron microscopy (SEM) with energy–dispersive X-ray spectrometer (EDS), and transmission electron microscopy (TEM). Hardness of the SPS sintered alloys was measured using micro Vickers hardness tester. The Al–Cr–Si bulks with high Cr and Si content were produced successfully using SPS sintering process without crack and obtained fully dense specimens close to nearly 100% T. D. (Theoretical Density). The maximum values of the hardness were 834 Hv for the sintered specimen of the gas atomized Al–30Cr–20Si alloy. Enhancement of hardness value was resulted from the formation of the multi-intermetallic compound with the hard and thermally stable phases and fine microstructure by the addition of high Cr and Si.

In this study, changes in the microstructure, mechanical properties, and electrical conductivity of as-cast and as-extruded Al–B based alloys with the addition of Fe and rare earth (RE) were investigated. The melted aluminum alloy was maintained at 750 °C and then poured into a mould at 200 °C. Aluminum alloys were hot-extruded into a rod that was 12 mm in thickness with a reduction ratio of 39:1. The addition of Fe and RE resulted in the formation of Al11RE3 and Al3Fe intermetallic compounds and the area fraction of these inter-metallic compounds increased with increasing Fe and RE contents. As the amount of Fe and RE increased, the average grain size of the extruded Al alloy decreased to 798.6, 196.1, and 21.9 µm, and the high-angle grain boundaries fraction increased to 24.8, 27.9, and 60.7%. In the case of cast materials, low electrical conductivity was shown by porosity and fine casting defects. As the Fe and RE contents increased, the electrical conductivity of the extruded Al–B alloy decreased to 62.3, 59.6 and 55.0% International Annealed Copper Standard. As the Fe and RE content increased the ultimate tensile strength improved from 90.8 to 112.9 MPa which was attributed to the grain refinement and formation of Al11RE3 and Al3Fe intermetallic compounds by the addition of Fe and RE.

The effect of addition of Mischmetal (MM) on the microstructure, electrical and thermal conductivity, and mechanical properties of the as-extruded Al-MM based alloys were investigated. The studied AlxMM alloys (where x = 0.2, 0.5, 1.0, 1.5, 2.0 and 5.0 wt.%) were cast and homogenized at 550 °C for 4 h. The cast billets were extruded into 12 mm bars with an extrusion ratio of 39 at 550 °C. The addition of MM resulted in the formation of Al11(Ce, La)3 intermetallic compounds and the area fraction of these intermetallic compounds increased with an increase in the MM content. The Al11(Ce, La)3 phase, which was distributed in the as-cast alloys, was crushed into fine particles and arrayed along the extruded direction during the extrusion process. In particular, these intermetallic compounds in the extruded Al-5.0MM alloy were distributed with a wide-band structure due to the fragmentation of the eutectic phase with a lamellar structure. As the MM content increased from 1.0 wt.% to 5.0 wt.%, the average grain size decreased remarkably from 740 to 73 μm. This was due to formation of Al11(Ce, La)3 particles during the hot extrusion process, which promoted dynamic recrystallization and suppression of grain growth. The electrical and thermal conductivity of the extruded alloys containing up to 2.0 wt.% MM were around 60.5% IACS and 230 W/m · K, respectively. However, the electrical and thermal conductivity of the extruded alloy with 5.0 wt.% MM decreased to 55.4% IACS and 206 W/m · K, respectively. As the MM content increased from 1.0 wt.% to 5.0 wt.%, the ultimate tensile strength (UTS) was improved remarkably from 74 to 119 MPa which was attributed to the grain refinement and formation of Al11(Ce, La)3 intermetallic compounds by the addition of MM.

High conductivity Al alloys are widely used for electric materials, heat exchangers, and heat dissipation parts such as electric conductors, transmission lines, communication cables, automobile wires and so on. In this study, the effects of Ca and Mn addition on the microstructure and mechanical properties of Al–0.3Cu–0.2Fe–0.15Si–0.15Zn alloys were investigated. The melt was held at 800 °C for 20 minutes and poured into a mold. The cast Al alloy was hot extruded with a rod having a diameter of 12 mm and a reduction ratio of 38:1. Al–0.3Cu–0.2Fe–0.15Si–0.15Zn–0.9Mn–0.4Ca alloy consists of Al, Al–(Fe, Mn)–Si, Al–(Fe, Mn) and Al–(Ca) intermetallic compounds. The formation of the intermetallic compound and this phase was broken in to small particles during extrusion. As the Ca content increased from 0 to 0.4 wt.%, the electrical conductivity of the extruded Al–0.3Cu– 0.2Fe–0.15Si–0.15Zn alloys increased by 57.3, 57.9 and 59.0 %IACS (International annealed copper standard). Al–0.3Cu–0.2Fe–0.15Si–0.15Zn–0.9Mn alloy with element additions of Ca, ultimate tensile strength was decreased from 178.3 to 163.2 and 151.8 MPa. However, the elongation was improved to 18.6, 21.6 and 23.15%.

In this study, we investigate the microstructure and mechanical properties of as-extruded Al-1.0RE alloys. The molten Aluminum alloy was maintained at 800 °C and then poured into a mould at 200 °C. Aluminum alloys were hot-extruded into a rod measuring 12 mm thick with a reduction ratio of 38:1. The microstructure and electric conductivity properties of as-extruded Al-1.0RE alloy under different annealing processes were investigated and compared. After extrusion, the intermetallic compound having a needle shape in the cast state was finely decomposed based on the direction of extrusion. Significant changes in the microstructure were detected after annealing at 500 °C with fragmentation and sphering of eutectic particles. The annealing temperature of Al-1.0RE alloy increased proportionally to the electrical conductivity. The formation of Al-RE intermetallic compounds increases the electrical conductivity and improves the mechanical properties of the alloy through precipitation hardening.

Microstructure and texture of P-type 75%Sb₂Te₃-25%Bi₂Te₃ alloy fabricated by using gas-atomization and extrusion processes was investigated. The microstructure of the gas-atomized powders exhibited fine grains with needle shape. After hot extrusion, grain size was characterized by fine and equiaxed grains due to dynamic recrystallization by severe deformation. (0001) basal planes of the extruded specimens were preferentially orientated parallel to extrusion direction. As extrusion temperature, fraction of the basal planes was increased.

In this work, Al-0.15Si-0.2Fe-0.3Cu-0.9Mn alloys with different Zn addition (0, 0.15 and 0.3 wt%) were melted and extruded at 200 °C. The effect of Zn on the microstructure, texture evolution and mechanical properties of Al-0.15Si-0.2Fe-0.3Cu-0.9Mn alloys was investigated using scanning electron microscope (SEM), equipped with energy-dispersive X-ray spectrometry (EDS) and electron backscatter diffraction (EBSD) and in the present study. In order to evaluate the mechanical properties, we implemented the tensile tests by a universal material test machine. Al-0.15Si-0.2Fe- 0.3Cu-0.9Mn-xZ resulted in the formation of Al-(Fe, Mn)-Si and Al-(Fe, Mn) intermetallic compounds. The formation of the intermetallic compound and this phase was broken in to small particles during extrusion. The ultimate strength and elongation of the as-extruded Al-0.15Si-0.2Fe-0.3Cu- 0.9Mn alloy were 96.51 MPa and 34.01%, while those of the Al-0.15Si-0.2Fe-0.3Cu-0.9Mn-0.3Zn alloy were 99.08 MPa and 36.21%, respectively. Al-0.15Si-0.2Fe-0.3Cu-0.9Mn alloys with Zn addition resulted in improving the strength with no reduction in elongation.

A significant enhancement in corrosion resistance by Y microalloying was achieved for the Mg–8Sn–1Zn–1Al (wt%) alloy in the extruded condition. Average corrosion rates obtained by immersion tests in 0.6 M NaCl solution at 25 °C were 4.2 and 12.7 mm y−1 for the alloys with and without microalloying with 0.04 wt% Y, respectively. Microstructural investigations indicated that the enhanced corrosion resistance is a result of a transition in a type of second-phase particles toward lowering the difference in electrochemical nobility between the α-Mg and these particles, thereby reducing the susceptibility of the alloy to microgalvanic corrosion.

In this study, microstructure and sintering behaviors of the gas-atomized Al-(25 or 30) Cr-xSi alloy (

Microstructure and properties of Al–2 wt.%Zn–1 wt.%Cu–xMg (x = 0.1, 0.3, 0.5, 0.7 wt.%) alloy extrusion materials were investigated. The lattice constants for the (311) plane increased to 4.046858, 4.048483, 4.050114 and 4.051149 Å with the addition of 0.1, 0.3, 0.5, and 0.7 wt.% of elemental Mg. The average grain size of the as-extruded Al alloys was found to be 328.7, 297.7, 187.0 and 159.3 μm for the alloys with 0.1, 0.3, 0.5, and 0.7 wt.% Mg content, respectively. The changes in the electrical conductivity by the addition of elemental Mg in Al–2 wt.%Zn–1 wt.%Cu alloy was determined, and it was found that for the addition of 0.1, 0.3, 0.5, and 0.7 wt.% Mg, the conductivity decreased to 51.62, 49.74, 48.26 and 46.80 %IACS. The ultimate tensile strength of Al–2 wt.%Zn–1 wt.%Cu–0.7 wt.%Mg alloy extrusion was increased to 203.55 MPa. Thus, this study demonstrated the correlation between the electrical conductivity and strength for the Al–2 wt.%Zn–1 wt.%Cu–xMg alloys.

The effect of addition of Mischmetal (MM) on the microstructure, electrical and thermal conductivity, and mechanical properties of the as-extruded Al-MM based alloys were investigated. The studied Al

In order to investigate the microstructure and mechanical properties on Al–25Cr–5Si (at%) alloy, a mixed powder with pure elements and an alloy powder using a gas atomization process were used. Fine and high purity Al–25Cr–5Si (at%) alloy powder was successfully prepared by gas atomization and densified using a spark plasma sintering (SPS) process. The overall powder size distribution of the mixed Al, Cr, and Si elemental powders was in the range of 10–15 μm. The atomized Al–Cr–Si alloy powder was fine and spherical in morphology and difficult to be formed by intermetallic formation. Densification was clearly confirmed at 1000 °C, with almost isolated pores formed, by clear removal of pores between particles, deformation of particles, an increase in the number of contacts, and a change in size between particles. As a result of XRD analysis of the sintered compacts, single phase was observed using the mixed powder, but the compact using gas atomization remained the alloy phase even at the process temperature. The Vickers hardness of the compacts by mixed powder was observed at 59.70 Hv and the compact using gas atomized powders on the temperature 1000 °C of the Vickers hardness increased to 702.6 Hv. The compressive yield strength of the compact with mixed powder was 195.24 MPa and the compressive strength of the compact with gas atomized powder increased to 802.07 MPa. It is considered not to be decomposed by the AlCrSi, Al13Cr4Si4 and Al8Cr5 phases sintering process, resulting from the improvement of mechanical properties. We have obtained a fine and high purity Al–25Cr–5Si (at%) alloy powder, which has been successfully manufactured by gas atomization. The atomized Al–Cr–Si alloy powder was fine and spherical in morphology and difficult to be formed by intermetallic formation. Alloy powders have been densified using a pulsed current-activated sintering (PCAS) process. The Vickers hardness of the compacts by mixed powder was observed at 59.70 Hv and the compact using gas atomized powders on the temperature 1000 ℃ of the Vickers hardness increased to 702.6 Hv. The compressive yield strength of the compact with mixed powder was 195.24 MPa and the compressive strength of the compact with gas atomized powder increased to 802.07 MPa.

In this research, effects of Zn and Cu content on microstructure, mechanical properties, electric and thermal conductivity of the as-extruded Al

Thermal properties and microstructure of Al-4 wt.% Zn-2 wt.% Cu–x (x = 2 wt%. Mg, 2 wt%. Sn, 0.7 wt.% Mg-0.7 wt.% Sn-0.7 wt.% Ca) alloys on cast and extrusion have been investigated with extrusion temperature of 400 °C. Al-4 wt.% Zn-2 wt.% Cu alloy was composed of Al and Al2Cu phases. By adding Mg contents, Al2Mg3Zn3 phase was increased and Al2Cu phase was decreased respectively. During hot extrusion, elongated in the extrusion direction because of severe deformation. The thermal conductivity with temperature and composition of as-extruded Al-4 wt.% Zn-2 wt.% Cu–x alloys decreases with adding 2 wt.% Mg, 2 wt.% Sn contents from 190.925 and 196.451 W/mK but thermal properties of addition of 0.7 wt.% Mg-0.7 wt.% Sn-0.7 wt.% Ca element slightly reduced from 222.32 to 180.775 W/mK. The ultimate tensile strength (UTS) for Al-4 wt.% Zn- 2 wt.% Cu alloy was 121.67 MPa. By adding 2 wt.% Mg contents, tensile strength was dramatically increased with 350.5 MPa.

We investigated the effects of Al-5.0wt%Ti-1.0wt%B addition on the microstructure and mechanical properties of the as-extruded Al-0.15wt%Si-0.2wt%Fe-0.3wt%Cu-0.15wt%Zn-0.9wt%Mn based alloys. The Aluminum alloy melt was held at 800 °C and then poured into a mould at 200 °C. Aluminum alloys were hot-extruded into a rod that was 12 mm in thickness with a reduction ratio of 38:1. AlTiB addition to Al-0.15Si-0.2Fe-0.3Cu-0.15Zn-0.9Mn based alloys resulted in the formation of Al3Ti and TiB2 intermetallic compounds and grain refinement. With increasing of addition AlTiB, ultimate tensile strength increased from 93.38 to 99.02 to 100.01 MPa. The tensile strength of the as-extruded alloys was improved due to the formation of intermetallic compounds and grain refinement.

Accumulative roll-bonding (ARB) is the most appropriate process for sheet-shaped materials because it can be carried out readily by utilizing the conventional rolling apparatus. In this study, a nanostructured AA1050/AA5052 Al alloy sheet was successfully fabricated by four-layer stack ARB process. The ARB of AA1050 and AA5052 alloy sheets was performed up to 6 cycles without a lubricant at ambient temperature. The sample fabricated by the ARB was a multi-layer aluminum alloy sheet in which AA1050 and AA5052 layers are alternately stacked. The layer thickness of the each alloy became thinner and elongated to the rolling direction with the number of ARB cycles. The grain size decreased with increasing of the number of ARB cycles, after 6 cycles it became about 180 nm in thickness. The fraction of high angle grain boundaries increased with the number of ARB cycles. The tensile strength also increased with the ARB, it reached 305 MPa which is about 2.1 times that of the as-received AA1050. The mechanical properties of a multi-layer AA1050/AA5052 alloy fabricated by the ARB were compared to those of the other materials.

Niobium-titanium alloy is attractive materials for industrials as a superconducting magnets to high critical magnetic field and supercurrent density at -283 °C. The Nb-Ti alloy has been shown in earlier work to exhibit Van Gosh Sky microstructures. They may also be accentuated by plastic deformation due to work and temperature exposure during deformation. In order to miniaturize the magnet generating the same magnetic field, it is necessary to increase the critical current density of the superconducting wire. When fabricating superconducting wires, it is important to increase critical current density by optimizing processing and annealing conditions. When the α-phase of the Ti rich phase is uniformly precipitated by the heat treatment, the non-superconducting α-phase is dispersed in the superconducting Nb-Ti matrix. It becomes a pinning point that serves to fix the magnetic flux, which improves the critical current density. Also, if the shape of the precipitate is changed by machining, the superconducting and non-superconducting characteristics are further improved. In the present study, we studied the fraction of α-Ti phase of strain amount through groove rolling and heat treatment. The specimens were processed by groove rolling at room temperature and strain of 2.0, 3.16, 4.28 and 5.57. A microstructural analysis of the Nb-Ti alloys was performed by field emission scanning electron microscopy (FESEM).

The exothermic reduction of oxides mixture (MoO3+2SiO2) by magnesium in NaF melt enables the synthesis of nanocrystalline MoSi2 powders in near-quantitative yields. The combustion wave with temperature of about 1000–1200 °C was recorded in highly diluted by NaF starting mixtures. The by-products of combustion reaction (NaF and MgO) were subsequently removed by leaching with acid and washing with water. The as-prepared MoSi2 nanopowder composed of spherical and dendritic shape particles was consolidated using the spark plasma sintering method at 1200–1500 °C and 50 MPa for 10 min. The result was dense compacts (98.6% theoretical density) possessing submicron grains and exhibiting hardness of 8.74–12.92 GPa.

Aluminum and its alloys are used in a wide range of industrial applications from low density, high strength and a variety of structural materials. In this study, the effects of Ca addition on the microstructure and mechanical properties of Al-1wt.%RE alloys were investigated. The melt was held at 800 °C for 20 minutes and poured into a mold. The cast Al alloy was hot extruded with a rod having a diameter of 12 mm and a reduction ratio of 38:1. Al-1wt.%RE alloy consists of Al, Al11RE₃ phase. The Al₂Ca phase is increased by increasing the Ca content to 0.2 to 0.4 wt.%. As the Ca content increased from 0 to 0.4 wt.%, the average grain size of the extruded Al alloy decreased by 739.8, 400.8 and 155.0 μm. The tensile strengths were increased to 74.25, 76.53, and 79.52 MPa. The electrical conductivity of Al-RE alloy with Ca addition decreased to 60.32, 58.15 and 57.89% IACS.

In this study, a combustion process for a TiO 2 + 0.12Al + (2.5 + 6 k )Mg + 0.021V 2 O 5 + k MgCl 2 ·6H 2 O mixture was studied to fabricate Ti-6Al-4V alloy spherical particles. From the temperature-time profiles, the average value of the synthesis temperature was estimated to be 1650 ± 20 °C. Based on FESEM observations, spherical shape particles were obtained when 0.05–0.1 mol MgCl 2 ·6H 2 O was added to the initial reaction mixture. Therefore, spherical alloy particles were achieved by consecutive processes of cooling and acid purification of the burned down sample. According to laser particle size analysis, the average diameter of the spheres was between 5 and 25 μm. A selective laser melting process was applied to build dense Ti-6Al-4V alloy samples. The tensile properties and the microhardness were evaluated and compared to those characteristics of a reference sample prepared from commercial Ti-6Al-4V alloy spherical powder.

The microstructure and compressive mechanical properties of squeeze casted Mg 15Li xAl (x = 0, 1, 3 and 5 wt%) alloys have been investigated. With addition of Aluminum (Al) in Mg 15Li alloy, the compressive yield strength is continuously increased and density is slightly decreased. This improved mechanical property is mainly attributed to the precipitation of Al Li intermetallic compounds into the β-phase and grain size refinement of β-phase. Accordingly, lightweight and high specific strength Mg Li Al alloys were developed successfully via proper addition of Al contents, resulted from favorable microstructural evolution.

Effects of Li addition (2%, 5%, 8% and 11%) on microstructure and mechanical properties of the as-cast and as-extruded Mg–6Al–2Sn–0.4Mn-based alloys were investigated. Mg–xLi–6Al–2Sn–0.4Mn (x= 2, 5, 8 and 11, mass fraction, %) alloys were cast under an SF6 and CO2 atmosphere at 700 °C. After homogenization heat treatment at 350 °C, cast billets were extruded with a reduction ratio of 40:1 at 200 °C. Li addition to Mg–6Al–2Sn–0.4Mn resulted in the formation of MgSnLi2 and MgAlLi2 and/or AlLi intermetallic compounds and random basal texture. With increasing Li addition, β-Li phase was increased and the average area fraction of precipitates increased. Compression yield strength was increased from 212 to 235, 242 and 239 MPa as Li content was increased from 2% to 5%, 8% and 11%, respectively. Elongation was remarkably increased above 60% in 11% Li alloy. It is probable that Li-containing phases play a significant role in the enhanced mechanical properties by Li addition.

Effects of yttrium (Y) addition on mechanical properties and fracture behaviors of the as-extruded Mg-Al-Ca based alloys at elevated temperature were investigated by a tensile test. After hot extrusion, the average grain size was refined by Y addition and eutectic phases were broken down into fine particles. Y addition to Mg-5Al-3Ca based alloy resulted in the improvement of strength and ductility at elevated temperature due to fine grain and suppression of grain growth by formation of thermally stable Al2Y intermetallic compound.

Microstructure and texture of

The microstructure and mechanical properties of as-extruded Al-0.1 wt%Si-0.2 wt%Fe- 0.4 wt%Cu-0.04 wt%Zr-xMn-xAlTiB (x = 1.0 wt%) alloys under various annealing processes were investigated and compared. After the as-cast billets were kept at 400 °C for 1 hr, hot extrusion was carried out with a reduction ratio of 38:1. In the case of the as-extruded Al-Si-Fe-Cu-Zr alloy at annealed at 620 °C, large equiaxed grain was observed. When the Mn content is 1.0 wt%, the phase exhibits a skeleton morphology, the phase formation in which Mn participated. Also, the volume fraction of the intermetallic compounds increased with Mn and AlTiB addition. For the Al-0.1Si-0.2Fe-0.4Cu-0.04Zr alloy with Mn and AlTiB addition from 1.0 wt%, the ultimate tensile strength increased from 100.47 to 119.41 to 110.49 MPa. The tensile strength of the as-extruded alloys improved with the addition of Mn and AlTiB due to the formation of Mn and AlTiB-containing intermetallic compounds.

Magnesium and its alloys are potential candidates for many automotive and aerospace applications due to their low density and high specific strength. However, the use of magnesium as wrought products is limited because of its poor workability at ambient temperatures. Mg-Li alloys containing 5-11 wt.% Li exhibit a two-phase structure consisting of a α (hcp) Mg-rich phase and a β (bcc) Li-rich phase. Mg-Li alloys with Li content greater than 11 wt.% exhibit a single-phase structure consisting of only the β phase. In the present study, we studied the effects of Y addition on the microstructure and mechanical properties of Mg-11Li-6Zn-0.6Zr-0.4Ag-0.2Ca based alloys. The melt was maintained at 720 °C for 20 min and poured into a mold. Then, the as-cast Mg alloys were homogenized at 350 °C for 4 h and were hot-extruded onto a 4-mm-thick plate with a reduction ratio of 14:1. The as-cast Mg-11Li-6Zn-0.6Zr-0.4Ag-0.2Ca-xY (x 0, 1, 3, and 5 wt.%) alloys were composed of α-Mg, β-Li, γ-Mg2Zn3Li, I-Mg3YZn6, W-Mg3Y2Zn3, and X-Mg12YZn phases. By increasing the Y content from 0 to 5 wt.%, the composition of the W-Mg3Y2Zn3 phase increased. With increasing Y content, from 0 to 1, 3, and 5 wt.%, the average grain size and ultimate tensile of the as-extruded Mg alloys decreased slightly, from 8.4, to 3.62, 3.56, and 3.44 μm and from 228.92 to 215.57, 187.47, and 161.04 MPa, respectively, at room temperature.

In this study, the effects of heat-treatment conditions on the densification, microstructure, and magnetic properties of Fe powder were investigated. The oxygen content of the Fe powders heat-treated in Ar and Ar-H2 atmosphere was much lower than that of the Fe powder heat-treated in air atmosphere. The density of the compacts of the Fe powder heat-treated in Ar and Ar + H2 atmosphere was higher than that of the compacts of Fe powders heat-treated in air. Oxygen content in the heat-treatment conditions played a significant role in the improvement of the densification and magnetic properties.

The microstructure of the as-cast Mg-5Al-3Ca-2Nd-xDy alloys consists of α-Mg matrix, (Mg, Al)2Ca eutectic phase, Al-Nd and Al-Dy intermetallic compounds. α-Mg matrix morphology was changed from dendritic to equiaxed with the increase Dy addition. And grain size was remarkably refined. As Dy content was increased, yield strength was improved due to the refined grains and the homogeneous distribution of Al-Dy phase.

Aluminum and its alloys, due to their low density, high specific strength and high corrosion resistance amongst various structural materials, are used in a wide range of industrial applications for different aqueous solutions. In the present study, we studied effects of Ce addition on microstructure and mechanical properties of Al-2Li-1Cu-0.8Mg-0.1Zr alloys. The melt was held at 780 °C for 20 min and poured into a mold. And as-cast Al alloys were hot-extruded into a plate that was 4 mm in thickness with a reduction ratio of 14:1. The extruded plates were held at 540 °C for 4 hr in water quenching to solution treatment them. As-extruded Al-2Li-1Cu-0.8Mg-0.1Zr-xCe (x = 0.3, 0.6, 0.9 and 1.2 wt.%) alloys are composed of Al, AlLi, AlCuLi and Al11Ce3 phases. By increasing the Ce content from 0 to 1.2 wt.%, the Al11Ce3 phase is increased, after solution treatment the AlLi and AlCuLi phases are decreased. With increasing Ce addition from 0 to 1.2 wt.%, the average grain size of the as-extruded Al alloys were decreased slightly from 100.7, 113.74, 84.3, 74.7 and 61.7 μm and ultimate tensile strength was decreased slightly from 267.59, 264.92, 237.40, 220.93 and 207.83 MPa at room temperature. After solution treatment, ultimate tensile strength was measured with 205.13, 198.12, 195.50, 198.27 and 208.01 MPa at room temperature.

In this research, the effects of applied pressure load and holding time on microstructure and thermoelectric properties of p-type Bi2Te3 + 75%Sb2Te3 alloys were studied. Besides this, the microstructural changes during the heat treatment of gas-atomized (GA) powders were examined. The grain growth (12.5–25 μm) was observed with increasing of the holding time of the heat-treated GA powders. The hot-pressed bulks showed grain refinement behavior with increasing pressure load, whereas grain size was found to slightly increase with increasing holding time. The peak power factor value, 3.48 W/mK2, was obtained for the hot-pressed sample at 420°C with pressure load of 530 MPa.

In this research, p-type Bi2Te3–75% Sb2Te3 thermoelectric alloy powders were produced by gas atomization and subsequently sintered by hot pressing at different temperatures. The grain growth of the hot-pressed samples was observed with increasing sintering temperature from 380°C to 460°C. The compressive strength increased with increasing hot-pressing temperature due to the high relative density of bulk samples obtained at high temperatures. The effect of sintering temperature on thermoelectric (TE) properties was studied. The maximum power factor 3.48 mW/mK2 was obtained for the sample hot pressed at 420°C due to the resulting high electrical conductivity and enhanced Seebeck coefficient values.

Microstructure and thermal properties of Mg–(3 mass% or 5 mass%) Sn–2 mass% Ca alloys as casts and extrusions have been investigated with different ram speeds and extrusion temperatures. Mg–(3 mass% or 5 mass%) Sn–2 mass% Ca alloys are composed of $$\upalpha $$ -Mg, MgSnCa, and $$\hbox {Mg}_{2}\hbox {Ca}$$ phases. By adding Sn content from 3 mass% to 5 mass%, the MgSnCa phase is increased and the $$\hbox {Mg}_{2}\hbox {Ca}$$ phase is decreased. During hot extrusion, the average grain sizes are increased with increasing ram speed and temperature. The ultimate tensile strength (UTS) and elongation for the Mg–5Sn–2Ca alloy at $$2.3\, \hbox {mm}{\cdot }\hbox {s}^{-1}$$ are 227.73 MPa and 18.43 %, respectively. With increasing extrusion ram speed, the UTS and elongation for the Mg–5Sn–2Ca alloy are remarkably decreased to 215.95 MPa, 206.33 MPa, and 14.74 %, 6.88 %, respectively. The thermal conductivity for the Mg–3Sn–2Ca alloy is dramatically improved, compared to commercialized Mg alloys such as AZ31 and AZ91 due to formation of MgSnCa and $$\hbox {Mg}_{2}\hbox {Ca}$$ phases.

In this study, the gas-atomized Cu-15%Ga alloy powder was consolidated by cross-roll rolling using copper can without crack and oxidation, where the roll axis was tilted by 5 degrees against TD in the RD-TD plane. Microstructures of formed Cu-15%Ga alloy were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), electron backscatter diffraction (EBSD) and optical microscopy (OM). Density of the cross-roll rolled specimens was measured using Archemeded method. Also, the porosity was examined by an image analyzer. The porosity of the cross-roll rolled samples with rolling reduction of 60% was approximately 6.7 times lower than that of the CR-rolled samples at 40% at a rolling temperature to 850 degrees C. The specimen obtained with 5 degrees of cross-roll rolling degree and 60% of rolling reduction ratio at 850 degrees C was above 99% to the theoretical density and an average grain size was 19.2 μm.

Effects of Li addition on microstructure and mechanical properties of as-cast and as-extruded Mg–xLi–3Al–1Sn–0.4Mn alloys were investigated. Mg–3 wt%Al–1 wt%Sn–0.4 wt%Mn alloys with different Li addition (5, 8 and 11 wt%) were cast under an SF6 and CO2 atmosphere at 700 °C and extruded at 200 °C. Li addition to Mg–3Al–1Sn–0.4Mn resulted in the formation of MgLi2Sn and MgLi2Al intermetallic compounds and random basal texture. With increasing Li addition from 5 to 8 and 11 wt%, ultimate tensile strength was decreased from 258 to 240 and 220 MPa. On the other hand, the elongation was improved remarkably from 16.0% to 15.4% and 35.1% at room temperature due to transformation from HCP to BCC crystal structure and a weaker basal texture. In the Mg–xLi–3Al–1Sn–0.4Mn alloys, MgLi2Sn and MgLi2Al intermetallic compounds played a significant role for the increase of the mechanical properties.