Tensile behaviour and fractography analyses of LM6/ZrO2 composites
Obnašanje in analiza pri natezni obremenitvi preloma kompozitov LM6/ZrO2

G. Karthikeyan, G. R. Jinu
2017 Materiali in Tehnologije  
Aluminium-based metal matrix (LM6) composite materials were prepared using various percentages of 0 %, 3 %, 6 %, 9 % and 12 % of zirconia by the weight fraction method and fabricated by the stir casting method. Five samples were prepared as per the ASTM B-557-M-94 standard, and then the prepared sample was subjected to an energy-dispersive spectrometry (EDS), hardness and tensile tests. The hardness and tensile test results revealed that the maximum hardness, maximum ultimate strength, yield
more » ... ength was obtained for the composite containing 12 % of mass fractions of ZrO2. The percentage of increase in zirconia increases the hardness, ultimate strength, yield strength. The minimum percentage of zirconia gives the minimum hardness and ultimate strength. Then EDS test was conducted on prepared samples. It was confirmed that aluminium and zirconia particles are present in the metal matrix composites. Fractography analysis was also employed in this work to understand the fracture mechanics of the surface. The fractography analysis was conducted with a scanning electron microscope (SEM). From the fractography analysis it was revealed that the nature of the fracture surface was changed from ductile with a large dimple surface to brittle fracture. Keywords: metal matrix composites, aluminium LM6 alloy, zirconia (ZrO 2 ), tensile test, fractography Kovinski kompoziti na osnovi aluminija (LM6) so bili pripravljeni z razli~nimi masnimi dele'i 0 %, 3 %, 6 %, 9 % in 12 % cirkonijevega dioksida, z metodo ulivanja z me{anjem taline. Pet vzorcev je bilo pripravljenih skladno s standardom ASTM B-557-M-94 in nato pregledanih z energijsko disperzijsko spektrometrijo (EDS), izmerjena je bila trdota in izvedeni so bili natezni preizkusi. Iz meritve trdote in nateznih preizkusov sledi, da je bila najve~ja trdota in najvi{ja natezna trdnost dose'ena pri kompozitu z 12 masnimi % ZrO2. Nara{~ajo~a vsebnost cirkonijevega dioksida povi{uje trdoto, natezno trdnost in mejo plasti~nosti. Najmanj{a vsebnost cirkonijevega dioksida daje najmanj{o trdoto in najni'jo natezno trdnost. Na pripravljenih vzorcih je bila izvedena tudi EDS analiza, ki je potrdila, da sta aluminij in delci iz cirkonijevega dioksida prisotna v kovinski osnovi kompozita. Analiza prelomov je bila tudi uporabljena v tem delu, da bi razumeli mehaniko preloma povr{ine. Analiza prelomov je bila izvedena z vrsti~nim elektronskim mikroskopom. Analiza prelomov je odkrila, da se narava povr{ine preloma spreminja iz duktilnega z velikimi jamicami, v krhek prelom. Klju~ne besede: kompoziti s kovinsko osnovo, aluminijeva LM6 zlitina, cirkonijev dioksid (ZrO2), natezni preizkus, analiza preloma
doi:10.17222/mit.2015.319 fatcat:gemv562hynekxdtiqhppxkwatm