Influence of La-Ce Mischmetal on Dendritical Arm Space and Ultimate Tensile Strength in ZL105 Alloys

The influence of pure La, pure Ce, (La+Ce) mischmetal on the dendritical arm space(LDAS) of ZL105 alloy in cylinderical casting was studied. The effects of adding amount of (La+ Ce) mischmetal on LDAs and ultimate tensile strength(b) were investigated, and the relationship between b and LDAS was founded. (La+Ce) mischmetal has stronger ability to refine LDAs than pure La or pure Ce. The proper adding amounts of it is 0.15% (mass fraction). LDAs has a remarkable effect on ah of casting, which can be predicted by the regression equation obtained in this work.

The Effects of Cupping Therapy on Skin’s Biomechanical Properties in Wistar Rats

Cupping therapy has been widely used for clinical treatment of soft tissue lesions. The current study investigated the effects of cupping therapy on biomechanical properties of the skin in Wistar rats. 20 rats were divided into two groups: 10 in experimental and 10 in control group. Either the right or the left lower quadrants of the lumbar regions in the experimental group underwent 10 minutes daily cupping therapy for 12 days. The skin stiffness and ultimate tensile strength of all the rats were measured using tensiometer. The skin stiffness and ultimate tensile strength were decreased significantly in cupping side of the experimental group as compared with the non-cupping side and the control group. There were no significant differences between the non-cupping side of the experimental group and the control group. In conclusion, cupping therapy can be useful as a treatment method to reduce the skin stiffness and ultimate tensile strength.

Characterization of the tensile properties of friction stir welded aluminum alloy joints based on axial force, traverse speed, and rotational speed

Friction stir welding （FSW） process has gained attention in recent years because of its advantages over the conventional fusion welding process. These advantages include the absence of heat formation in the affected zone and the absence of large distortion, porosity, oxidation, and cracking. Experimental investigations are necessary to understand the physical behavior that causes the high tensile strength of welded joints of different metals and alloys. Existing literature indicates that tensile properties exhibit strong dependence on the rotational speed, traverse speed, and axial force of the tool that was used. Therefore, this study introduces the experimental procedure for measuring tensile properties, namely, ultimate tensile strength （UTS） and tensile elongation of the welded AA 7020 A1 alloy. Experimental findings suggest that a welded part with high UTS can be achieved at a lower heat input compared with the high heat input condition. A numerical approach based on genetic programming is employed to produce the functional relationships between tensile properties and the three inputs （rotational speed, traverse speed, and axial force） of the FSW process. The formulated models were validated based on the experimental data, using the statistical metrics. The effect of the three inputs on the tensile properties was investigated using 2D and 3D analyses. A high UTS was achieved, including a rotational speed of 1050 r/min and traverse speed of 95 mm/min. The results also indicate that 8 kN axial force should be set prior to the FSW process.

Effect of Transverse Grain Boundary on Microstructure,Texture and Mechanical Properties of Drawn Copper Wires

In the present study, microstructure and texture of drawn copper wires with a large number of transverse grain boundaries have been characterized and their mechanical properties have been analyzed. The results show that the texture evolution is accelerated by transverse grain boundary and the saturation value 60% of volume fraction of 〈111〉 fiber texture component is reached rapidly with increasing strain. For the microstructure of drawn wires with a large number of transverse grain boundaries, the critical strain, where lamellar boundaries form, is less than that for wires with equiaxed grains or columnar grains （all grain boundaries parallel to axis direction）. Since transverse grain boundary accelerates grain subdivision and dislocation density increases rapidly in drawn wires with a large number of transverse grain boundaries, there are a higher flow stress and a higher work hardening rate.

Microstructure and properties of as-cast Cu-Cr-Zr alloys with lanthanum addition

Cu-0.45 Cr-0.2 Zr-xLa（x = 0-0.48） alloys were prepared by vacuum casting. The effects of La addition and orientation on the microstructure and properties of the as-cast alloy were investigated by an optical microscope, a scanning electron microscope with an energy dispersive X-ray spectrometer, a tensile testing machine and an electrical conductivity tester. The result shows that the addition of La significantly refines the columnar grainsize and decreases the secondary dendrite arm spacing. Trace addition of La improves the room temperature ultimate tensile strength,elongation and electrical conductivity mainly by purifying during melting and casting. The ultimate tensile strength, elongation and electrical conductivity significantly decrease with the increase of La content due to formation of coarse particles and oxides, which severely harm the performance of the Cu-0.45 Cr-0.2 Zr-xLa alloys. The Cu-0.45 Cr-0.2 Zr-0.13 La alloy possesses a good combination of room temperature ultimate tensile strength, elongation and electrical conductivity. In addition, room temperature ultimate tensile strength and electrical conductivity along transverse direction of the ingot are higher than that along longitudinal direction,which is mainly ascribed to different distribution of grain boundary and grain orientation.

Effect of Electromagnetic Stirring on the Distribution of Nb Phase in Cu-5wt%Nb Alloys

The effect of electromagnetic stirring(EMS)on the distribution of Nb particles in solidified microstructure of a Cu-5wt%Nb alloy were studied.In this paper,we have Cu-5wt%Nb alloy remelted and solidified with or without electromagnetic stirring,to study the effect of EMS on the distribution of Nb phase and the hardness of ingots.The 300A/16Hz EMS has refined the mircostrucrure of Cu-5%Nb alloy,with smaller particles sizes and larger amounts,and is benefit to the homogenous distribution of particles.The fitted lognormal distribution of particles diameter that in case without or with EMS are compared,and the EMS case has the highest frequency percentage in the range of smaller size. EMS considerably increased the hardness of Cu-5%Nb alloy ingot.

Effect of Magnetic Field on Solidification Microstructure of Cu-20wt%Nb Alloys and Properties of the In-Situ Deformed Wires

Magnetic field has great impact on the second phase distribution in metal solidification process.In this paper, we have Cu-20wt%Nb alloy remelted and solidified with or without the imposition of magnetic field,to study the effect of magnetic field on the distribution of Nb phase and the properties of deformed wires.Magnetic field has an inhibiting effect on the ripening process of Nb particles,and is benefit to the prolongation of Nb-rich phase in deformed wires.Both the ultimate tensile strength and conductivity in 1 T case is larger than that in 0 T case.

Hybridization of graphene-reinforced two polymer nanocomposites

This article focuses on the hybridization of thermoplastic polymer matrices with conducting polymers and graphene derivatives.Polypropylene(PP),polymethylmethacrylate(PMMA)and polyox-ymethylene(POM)were used as primary polymer matrices and polypyrrole(PPY)and polyaniline(PANI)as secondary conducting polymers.Highly conductive-reduced graphene oxide(rGO)and graphene(G)have been used as reinforcements.A Taguchi analy-sis has been performed for the blends to find the optimal combi-nation of the blends with respect to electrical conductivity(σ)and mechanical properties.Both electrical and mechanical properties were improved by the hybridization process.The maximum elec-trical conductivity of 0.85 S.cm^(−1) has been acquired with POM/PPY/G blend with 3 wt.%and 5 wt.%of PPY and graphene load-ing,respectively.The mechanical properties have been found to improve with all the blends but,PP/PPY/G blend with 3 wt.%and 6 wt.%of PPY and graphene loading displays overall better prop-erties in comparison with other blends.