Abstract:
The aim of this work is according to the feasibility of replacing the ABNT2224 aluminum alloy, the main rotor blade material of the Robinson R22 Beta II helicopter by ABNT 7075 aluminum alloy or polymer matrix and carbon fiber reinforcement unidirectional composite, in order to evaluate the increasing of the useful life, mechanical resistances and costs reduction. In the longitudinal and transversal sections aluminum alloys, ABNT 2224 and 7075, were used to perform the metallographic analysis and Vickers hardness with micro loading. Afterwards there were made test specimens for tensile tests for aluminum alloys, ABNT 2224 and 7075, flexure and impact for aluminum alloy ABNT 7075 in order to obtain its mechanical characteristics. It was possible to observe similarity in the hardness values of 140 HV0,2kg in average and a resistance limit of 330MPa- 340MPa, but there was a divergence in the yield limit values considering the change. It has concluded that in relation to mechanical properties, hardness and cost reduction the replacement of ABNT 2224 aluminum alloy by ABNT 7075 aluminum alloy is feasible. Unidirectional composites of 3mm and 4,5mm thickness were laminated, and after that specimen test, the same tests had been done for traction, flexure and impact as well as for aluminum alloys. It was possible to observe elastic modulus values, resistance limits higher than the aluminum alloys values, but when comparing them of absorbed energy in the impact test it was possible to observe lower values, the substitution is feasible if the blade is impacted lower values than obtained.