Improvement of Mechanical Properties of 2024 AA by Reinforcing Yttrium and Processing Through Spark Plasma Sintering

Abstract

The need for developing new methods to fabricate metal matrix composites is a never-ending process, which drove to the development of more facilitated fabricating methods like field-assisted sintering, etc. The main objective of the present experimental study is to develop aluminium 2024 alloy-based metal matrix composites by very little amounts of yttrium reinforcement through field-assisted sintering also called as spark plasma sintering (SPS) and to analyse the relationship between the mechanical properties and corresponding microstructure. Composite samples consisting of aluminium 2024 alloy matrix and yttrium reinforcement, starting from 0.1 to 0.5% by weight, are developed through SPS. Computerized Vickers testing machine is used to determine the hardness of the composite samples. The metallurgical characterization of the composite samples is assessed by optical microscopy, scanning electron microscopy and X-ray diffraction. To compare the influence of yttrium on the composite samples developed, pure 2024 aluminium alloy sample is also sintered. It is found that an optimum amount of yttrium reinforcement (0.3 wt%) creates favourable conditions for strengthening mechanisms to achieve peak properties. Then the properties tend to decrease gradually when yttrium content is increased beyond 0.3% by weight. The highest hardness, ultimate tensile strength and yield strength are found to be 114 HV, 388 and 343 MPa, respectively, with 18.4% elongation in the composite reinforced with 0.3 wt% yttrium. The mechanical properties are in close agreement with the microstructures and grain sizes. High density and improved tensile properties are achieved in the present composites developed through spark plasma sintering.