Study of the mechanical properties of Iron-Epoxy composite materials

Iron-Epoxy composite samples were prepared by addeddifferent weight percentages (0, 5, 10, 15, and 20 wt %) from Ironparticles in the range of (30-40μm) as a particle size. The contentswere mixed carefully, and placed a circular dies with a diameter of2.5 cm. Different mechanical tests (Shore D Hardness, Tensilestrength, and Impact strength ) were carried out for all samples. Thesamples were immersed in water for ten weeks, and after two weeksthe samples were take-out and drying to conducting all mechanicaltests were repeated for all samples. The hardness values increasedwhen the Iron particle concentration increased while the Impactstrength is not affected by the increasing of Iron particlesconcentration. The tensile strength results reveal that the tensilestrength and the strain values of composite samples decreases whenthe Iron particles concentration increase. After conductedimmersion processes the results of hardness are reduced wears theresults of tensile strength and the impact strength are increased.


Introduction
Polymeric composite materials are of versatile scientific and technological significance due to their enhanced mechanical properties, and Epoxy resin as a part of polymeric materials is widely used as an electrical insulation material [1]. However it is fracture behavior is brittle compared with metals, therefore it is necessary to improve the mechanical properties of epoxy resin by adding other materials. Low cost particulate fillers are added to epoxy in commercial production primarily for reasons of economy and improvement in molding characteristics [2][3][4]. Metal particles added to polymeric materials lead to composite with higher density, improved electrical and thermal conductivity, and are therefore of particle interest for specific applications [5]. In 2001 Deya study the effect of Nitric acid, Hydrochloric acid, and UV radiation on mechanical properties of epoxy -fiber glass composite samples and in other time on epoxy-alumina composite and it is found that the effect of solutions acids is bigger than that effect of UV-radiation [6]. Firas was study the effect of environmental on fracture mechanism by impact on epoxyfiber glass and epoxy -metallic wires [7]. The composite means two or more from different materials participation sharing subscription association together fractions volume or weight percentages to produce new material of better properties, and in general the composites are classified into three kinds as follows [8,9]: І-Fiber composite: In this type the reinforced material is fibers include matrix material. ІІ-laminated composite: contains two or more layers from different materials are engagements together. ІІІ-Particulate composite: the reinforced material is a metallic or nonmetallic particle dispersed in matrix material as shown in the present work. The properties of any composite can be limited by three points; matrix Material, Reinforcement Material, and Interface of Bonding.

Experimental part Composite Iron / Epoxy resin preparation
Epoxy Resin used in this research was quick mast 105 which is involved two materials or two components; base epoxy in the form of liquid and hardener was added the transform to solid state of in a percentage of 3:1. Iron particles of average grain size of 30 μm and was added to Epoxy in a weight percentages of 0, 5, 10, 15, and 20 wt % and mixed carefully in a circular dies to make the composite samples.

Hardness testing
Shore D Hardness product of Time Group inc. company was used to conduct the Hardness measurement by using dibbing tool. The pointed dibbing tool penetrates in to the sample surface by the pressure applied on the instrument.

Impact testing
Impact test product of Amityville inc. company was used a chivied impact test for all samples by using fixed lever on the gauge. The potential energy by a swinging movement will be convert to kinetic energy, and will be lose a part of this energy in breaking of sample; then gauge will be read breaking energy of sample, and the Impact strength was calculated by employing the following equation [10,11].
The quantity usually measured is the energy absorbed in breaking of specimen in a single blow.

Tensile strength
Tensile strength is indicated by the making of a stress -strain Curve and in general indicate when necking will occur. As it an intensive property, the value does not depend on the size of the test specimen. It is however dependent on the preparation of the specimen and the temperature of the test environment and material [12]. Fig. 1 represents the shore D hardness values as a function of Iron particle concentration in composite samples before and after immersion in water for two weeks. From Fig. 1 can be seen that the shore D hardness values increased with the increasing of Iron concentration, this result may be related to the iron particle will be entire the cavities between epoxy resin particle, and then reduce these cavities and this behavior leads to increase the resistance samples to indentation. After immersion all samples in water for two weeks the values of shore D hardness still fixed for pure sample where hardness values reduced for other samples because of the water will be entire in to composite samples close to Iron particle zone and then separate between iron particle and epoxy resin.

Impact strength Results
Impact test was done by using Charpy method to evaluate the impact strength. Fig. 2 reveals that the impact strength values for all samples before and after immersion in water are decreased when the Iron particle concentration increased because of that the ability of epoxy resin to absorb the impact energy is greater than composite samples (epoxy/Iron), this conclude related to the Iron particle will be resists the impact energy and the ability to absorb this energy is less than that of pure samples. After immersion all samples in water for two weeks the values of impact strength are increased for all samples (pure epoxy and epoxy/Iron composite samples) with increasing of Iron particle concentration, the reason of this behavior related to that the water will be entire the specimens and become more flexible and the ability to absorb the impact energy will be improved.

Fig. 2: Impact strength (KJ/m 2 ) values as a function of Iron particles (wt%).
Tensile strength results Fig. 3 shows the tensile strength values as a capacity of Iron particles fixation in composite specimens previously, then after the fact inundation in water for two weeks. From this figure one can be demonstrated that rigidity qualities expanded with the expanding of Iron focus up to 10 wt% of Iron particles, this result may be identified with the iron particles will be decreased the yield purpose of composite examples, while Fig. 4 shows the strain as a capacity of Iron particles fixation, and can be demonstrated the strain qualities are diminished when the iron particles fixation expanded up to 10wt%.

Immersion results
The results of all mechanical tests after different periods (2,4,6,8, and 10) weeks of immersion in water for all specimens are tabulated in Table 1. From this table can be noticed the shore D hardness values are decreased when the immersion in water periods are increased. The impact tests values revealed that the impact strength increased with the increasing of immersion in water periods The tensile strength values increased when the immersion in water periods are increased.

Conclusions
The main remarks of conclusion can be summarized as follows: -The shore hardness values of epoxy / Iron particles composite increased when the Iron particles percentages increased.