Effect of Pre/Post Heat Treatment on the Friction Stir Welded SSM 356 Aluminum Alloys

The butt joints of semi solid 356 were produced in as cast conditions by friction stir welding process (FSW). This experiment studied in pre/post heat treatment (T6) using the welding speed 160 mm / min with tilt angle tool at 3 degree and straight cylindrical tool pin. The factors of welding were rotating speed rates at 1320, 1750 rpm and heat treatment conditions. They were divided into (1) As welded (AW) joints, (2) T6 Weld (TW) joints, (3) Weld T6 (WT) joints, (4) T6 Weld T6 (TWT) joints, (5) Solution treated Weld Artificially aged (SWA) joints and (6) Weld Artificially aged (WA) joints. Rotating speed and heat treatment (T6) condition were an important factor to micro, macro structure of metal and mechanical properties of the weld. Increasing rotating speed and different heat treatment condition impacted onto tensile strength due to the defects on joints. Therefore the optimum welding parameter on joint was a rotating speed 1320 rpm, the welding speed 160 mm/min, heat treatment condition of Weld T6 (WT) which obtained the highest tensile strength 228.92 MPa, as well as, highest hardness of 98.1 HV

Effect Of Layering Sequence On Mechanical Properties Of Hybrid Oil Palm Empty Fruit Bunch/Kenaf Fibre Reinforce Epoxy Composites

This paper presents the characterization on mechanical properties of hybrid oil palm empty fruit bunch (OPEFB)/kenaf reinforced epoxy composites at varying fibre layering sequence. OPEFB and kenaf in the form of short fibre (designated as OPs and Ks) and woven kenaf (Km) were used to form the final hybrid composites. All samples were characterized in accordance with ASTM D3039-14 for tensile test, ASTM D790-10 for flexural test and ASTM D256-10 for impact test. Results obtained revealed that the hybrid composites maximum tensile strength (26.876 MPa), tensile modulus (2.974 GPa), flexural strength (77.911 MPa), impact toughness (1.672 kJ/m2) and impact energy (1.24 J) value was obtained for Km/OPs/Km layering sequence, while the minimum value for all mechanical properties was obtained for OPs/Ks/OPs layering sequence. Moreover, highest value for flexural modulus (3.470 GPa) was obtained for Ks/OPs/Ks layering sequence. In conclusion, layering sequence with more woven kenaf layers improved the final hybrid composites mechanical properties compared to short fibre kenaf due to longer fibre length and fibre orientation. The final hybrid composites mechanical strength is also greatly influenced by the strength of the extreme outer layer fibres within the laminates, as well as the fibre orientation (either woven or randomly oriented)