Journal des sciences et de l'ingénierie des matériaux

Compressive creep tests have been carried out on zinc-rich alloys No.2 (Zn-4% Al-2.8% Cu-0.03% Mg), ACuZinc5 (Zn-3% Al-5.2% Cu-0.04% Mg) and ACuZinc10 (Zn-3.5% Al-9.3% Cu-0.03% Mg) in the stress range 20 to 100 MPa and at 70 to 160°C. Along with creep, other properties of ACuZinc alloys are claimed to be better than conventional zinc alloys No.3 and No.5, and ZA alloys. The primary creep contraction was generally found to increase with increasing copper content in a non-linear fashion. The secondary creep rates of No.2 were slightly lower than those of ACuZinc5 and ACuZinc10. Based on the above equation, continuous design stresses were calculated under different testing conditions which showed that both ACuZinc alloys were inferior in creep strength to No.2 due to its lower secondary creep rates. The results and microstructure of alloys also showed that in all three alloys, the creepcontrolling mechanism is the dislocation climb over second-phase (ε) particles.

The material and mechanical properties of samurai swords (Japanese swords), made using a traditional steelmaking technology (tatara), are investigated experimentally. The quality of these swords appears to be low because of the presence of a large number of inclusions, including oxide- and phosphorus-based structures; however, their mechanical properties are relatively good because of their fine-grained structure and high residual stress. The swords consist of several carbon steels, with a fine microstructural formation being obtained in the sharp edge of the sword (knife) as a result of the forging process. There is high residual compressive stress in the thick edge of the sword (mandrel), caused by bending due to the martensitic phase transition in the sharp edge. The carbon content of the sword varies depending on region: the sharp edge is found to have 0.55% C, which is more than twice the amount in the thick edge. The Vickers hardness and tensile strength in the sharp edge region are about 6 and 1 GPa, respectively, which are about three times higher than the corresponding values in the other regions of the sword. The hardness in the sharp edge region is almost the same as in a conventional carbon steel (Fe-C0.55) produced by presentday steelmaking technology. The tensile strength of the sharp edge of the sword is relatively high, but is slightly lower than that of the conventional Fe-C0.55 steel, despite the fine-grained structure and high residual compressive stress in the sharp edge region. This is caused by the presence of various inclusions in the sword.

This article addresses the experimental characterization of the temperature aging effect on tensile fracture load behavior of notched and unnotched high density polyethylene material. The samples were cut from a HDPE pipe. After mechanizing the tensile specimens with a numerical controlled machine, two series of samples were mechanized with different types of notches. The first series was drilled with a different central hole of diameter 4,6 and 8 mm. In the second series, one group of specimens the V shape notches were carried out on one side of samples, while for the second group the V shape notches were carried out on the double sided of specimens. Once the notches mechanized, the samples were exposed into a room temperature to positive and a negative temperatures -40?C and 100?C during 72 hours. The planning design experiment approach was applied to obtain a mathematical model taking account all the influencing parameters on tensile fracture load of the material. The fracture tensile load and the elongation in cases of V and circular notch were modeled as function of temperature aging effect. From the response surfaces of both cases, we note that the temperature had a significant effect on fracture load tensile and elongation with respect on type of number of V notch and hole diameter. The ultimate tensile load decrease and the elongation increases.

Specific chemical environments step out in the industry objects. This paper presents experimental investigation results of the chemical resistance of special polymerized sulfur composite impregnated concrete and cement mortar. The special polymerized sulfur composite applied as the industrial waste material. The process of special polymerized sulfur composite as the industrial waste material production is a thermal treatment process in the temperature of about 150-155°C. The result of such treatment is special sulfur composite in a liquid state. Special sulfur composite in a liquid state is mixed with previously heated extender. In the paper there is presented development of the special polymerized sulfur composite as the industrial waste material, along with the practical uses in building industry. Also this paper presents the results of the experimental research and analyses indicating the usefulness of special polymerized sulfur composite to the protection against corrosion of concrete and cement mortar. In this paper the review of the literature have been done, among other things about select using special polymerized sulfur composite in buildings, about the methods of the surface protection against corrosion of concrete and about the methods of the evaluation of protection layer on these materials. Also in paper presents materials also the domain of the personal investigations and the methodology are definite. The research has comprised the compositions and the conditions for the formation of materials. The physical and mechanical properties of special polymerized sulfur composite have been evaluated. After the analysis of the initial results the optimum compositions have been chosen to the experimental research. In this paper the usefulness of special polymerized sulfur composite to the surface protection against corrosion of the concrete and cement mortar have been evaluated. Special polymerized sulfur composite impregnation of lean concrete and cement mortar increases its compressive strength from less than 1/3 to 1-1/2 times that of high strength concrete. Maximum absorption of special polymerized sulfur composite is achieved by carrying out the impregnation in molten sulfur under vacuum. Recent work indicates that satisfactory impregnation levels may also be achieved without the use of vacuum. Studies also show that while impregnation of high strength concrete and cement mortar increases its final strength to a value higher than that of low strength concrete, the relative increase in strength and the amount of special polymerized sulfur composite absorbed are smaller. Special polymerized sulfur composite impregnated concrete and cement mortar (SIC) may be used where high strength, resistance to water penetration, chemicals etc. are required. Available impregnating technology is applicable to precast concrete and cement mortar structures, while suitable technology for impregnating cast-in-place concrete needs to be developed. The impregnation of building materials such as blocks and bricks with melted special polymerized sulfur composite increases the compressive strength by a factor of 2 and modulus of elasticity by a factor of 3. The permeability of special polymerized sulfur composite impregnated materials to water and salt solutions is also greatly reduced. Due to the large surplus of sulphur and the low price, special polymerized sulfur composite impregnation of building materials will find extensive use in tall building construction. The space in concrete and cement mortar resulting from porosity reduces strength, exposes the concrete to chemical attack and, if filled with water, leads to destructive frost action at low temperatures. Filling the pores permanently and completely with an inert solid appears to be an effective way to improve mechanical properties and durability. Laboratory studies of impregnation with polymers have indicated that this is beneficial. New developments in concrete and cement mortar special sulfur polymer materials have declined in the Poland. There are still many products that are widely used, but the growth of these materials seems to have stabilized. A brief summary of new products related to special sulfur polymer composite impregnation, repair, overlays and precast polymer concrete will be presented. Sulfur polymer composite impregnation, which has received little attention in recent years, currently has some very interesting applications. Repair materials, particularly low modulus sulfur polymer concretes, have proven to be very effective. An innovative overlay for use in areas where freezing and thawing is prevalent has been developed.

The cerium-modified polymeric nanofilm of 6-(N,N-dibutyl)amino-1,3,5-triazine-2,4-dithiol monosodium (DBN) was fabricated by two-step potential electrodeposition onto aluminum alloy for corrosion protection. The structure, surface wettability and corrosion protection of the polymeric nanofilm were investigated by means of fourier transform infrared spectroscopy (FT-IR), water contact angle (WCA), open-circuit potential (OCP), potentiodynamic polarization and electrochemical impedance spectroscopy (EIS), respectively. FT-IR result revealed that DBN monomer had successfully been polymerized on aluminum alloy surface by electrochemical deposition in the absence and presence of cerium and the addition of cerium had no influence on FT-IR of the polymeric nanofilm. The result of surface wettability showed that WCA of aluminum alloy cerium-modified polymeric nanofilm was slightly higher compared with that without cerium. Electrochemical measurements demonstrated that the cerium-modified polymeric nanofilm on aluminum alloy surface exhibited remarkable corrosion protection property, which could be ascribed to the precipitation of cerium oxides or hydroxides on aluminum surface or the coordination between cerium and heterocyclic π-electron in polymeric nanofilm to prevent corrosive particles to the surface of aluminum substrate.

Loss of the lower limb can cause loss of mobility. At all places and at all times, efforts have always been made to make up for such a loss. The basic of this research new polymer blend self-cure PMMA/SR which can be used in manufacturing the prosthetic foot with a reasonable cost and satisfying mechanical properties accepted. Improvement tensile strength of this polymer blends for this application, one of the simple improve tensile strength of PMMA/SR polymer blend reinforcement by carbon fiber CF. Polymer blends (PMMA:SR) 90:10; 80:20; 70:30; 60:40; 50:50 were prepared reinforcements each one by carbon fibers from 5-15% (CF), then tensile strength test was carried out for prepared specimens, and effect of reinforcement by carbon fibers on tensile strength of polymer blends were determined as one improvement for prosthetic foot material.

Membrane distillation (MD) is a hybrid separation technique increasingly used in various fields such as desalination and the food industry. In this work, we present three theoretical models of flow and heat and mass transfers in membrane distillation unit air gap (AGMD). The results on the effect of membrane pore size have been analyzed for the different mechanisms of mass transfer involved by estimating the flow of generated steam. A mathematical model was presented for determining exchanges and possible combinations.

By means of X-ray follow-up and Contact Micro Radiography (CMR), new bone formation around the implants was investigated. And cytopathological observation was performed on the surrounding tissue. Regarding to the implants, microscopic observation was performed on the removed implants surface. Furthermore, metal element analysis was carried out to investigate chromium ion release as a sign of the galvanic corrosion.

In order to investigate the in-vivo galvanic corrosion, the plates and screws made of SUS and Ti64 were implanted into the proximal tibia of the rabbits for 52 weeks. The plate and screws were implanted in 4 different combinations of pairing up in different metals and identical metals

By means of X-ray follow-up and Contact Micro Radiography (CMR), new bone formation around the implants was investigated. And cytopathological observation was performed on the surrounding tissue. Regarding to the implants, microscopic observation was performed on the removed implants surface. Furthermore, metal element analysis was carried out to investigate chromium ion release as a sign of the galvanic corrosion.

In X-ray follow-up and CMR, the bone tissue under the plates became thin and porous like as concellous bone in all the combinations, which is supposedly due to the stress shielding and the disturbance of periosteal blood flow by the implantation. In the surrounding soft tissue and bone tissue, no remarkable findings were obtained in the cytopathological observation.

Regarding to microscopic observation of the implants, short striations with metallic luster in SUS implants, and short striations with metallic luster or dark brown color in Ti64 implant were confirmed. However these are supposedly caused by the scratching or frictional damage during the screw fixation.

In metal element analysis, the Cr element elution was confirmed around the SUS plates. However, there is no significant difference between SUS screw (identical metals) and Ti64 screw (different metals).

As the results, the in-vivo galvanic corrosion and related changes were not confirmed in all investigations at 52 weeks.