Evaluation of drilled hole quality of Al-Si alloy/fly ash composites produced by powder metallurgical technique

414-420<span style="font-size:9.0pt;mso-bidi-font-size:10.0pt;mso-bidi-language: TA" lang="EN-US">Metal matrix composites have high strength to weight ratio, high toughness, high impact strength, low sensitivity to temperature changes and high surface durability. In the present study, aluminium silicon alloy - fly ash composites are developed using powder metallurgy technique. Aluminium silicon alloy powder is homogenously mixed with fly ash and uniaxially compacted<span style="font-size:9.0pt;mso-bidi-font-size:10.0pt;mso-bidi-font-weight: bold;mso-bidi-font-style:italic" lang="EN-US">. The green compacts are sintered at the temperature of 600ºC. The <span style="font-size:9.0pt; mso-bidi-font-size:10.0pt" lang="EN-US">micro structural characterization<span style="font-size:9.0pt;mso-bidi-font-size:10.0pt;mso-bidi-language: TA" lang="EN-US">, hardness and <span style="font-size:9.0pt;mso-bidi-font-size: 10.0pt" lang="EN-US">drilled hole quality <span style="font-size:9.0pt; mso-bidi-font-size:10.0pt;mso-bidi-language:TA" lang="EN-US">in terms of surface roughness, diameter error and roundness error were studied on Al-Si alloy and Al-Si alloy - fly ash composites. Microstructure proved that the fly ash particles are located in grain boundary after sintering. The hardness of Al-Si alloy - fly ash composites is higher than that of Al-Si alloy due to grain refinement. The surface roughness of Al-Si alloy - fly ash composites increased with increasing speed, feed and fly ash content. The <span style="font-size: 9.0pt;mso-bidi-font-size:10.0pt;mso-bidi-language:TA" lang="EN-US">diameter error of Al-Si alloy and Al-Si alloy - fly ash composites is higher than that of roundness error. </span

Mechanical, DMA and Sound Acoustic behaviour of Flax woven fabric reinforced Epoxy composites

In this current investigation, alkali and Trimethoxymethylsilane treated custom made (irregular type) basket woven fabric at different weight percentages (0, 25, 35 and 45 wt.% and named as Pure epoxy, 25 FE, 35 FE, and 45 FE respectively) were reinforced with epoxy resin to develop flax/epoxy composites and tested for mechanical, dynamic mechanical, and sound absorption properties as per ASTM standards. Mechanical results revealed that, amongst the composites, 45 FE showed highest tensile strength, flexural strength, Impact strength and Shore D hardness of 91.07 MPa, 109.5 MPa, 295.65 J m ^−1 , and 85.23 respectively, whereas ILSS property did not shows much appreciable progress even at high fiber loadings. Dynamic mechanical analysis (DMA) tests were conducted for five different frequencies (0.5, 1, 2, 5, and 10 Hz) at varying temperature and properties such as storage modulus (E′), loss modulus (E″), and damping (tan δ curve) were evaluated. DMA properties of the composites have found to be improved after reinforced with the treated flax fabric. Effectiveness coefficient (C) confirms that 45FE composites exhibited better strong fiber-matrix interface and shows good agreement with cole-cole plot analysis. Sound absorption performance of the composites were determined in terms of sound absorption coefficient (SAC) using Impedance tube system for the frequency range 0–6400 Hz. Results indicated that flax-epoxy composites exhibit better sound absorption properties at medium and higher frequency levels. SEM analysis was carried out to understand the cause of failure in mechanically fractured composites. Moreover, morphologies of the fibers were also studied by XRD technique