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Properties of Graphite‐Strengthened Magnesium
Author(s) -
Ferkel H.
Publication year - 2003
Publication title -
advanced engineering materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 114
eISSN - 1527-2648
pISSN - 1438-1656
DOI - 10.1002/adem.200320503
Subject(s) - materials science , ball mill , graphite , powder metallurgy , ultimate tensile strength , extrusion , metallurgy , magnesium , creep , particle size , composite material , sintering , chemistry
Mg was dispersion‐strengthened with graphite by powder metallurgy. The material was produced by ball milling Mg micropowder (median particle diameter 40 μm) with 3 vol.‐% graphite powder (median particle diameter 1–2 μm). After 8 h ball milling the product was consolidated by hot extrusion. Structural analysis revealed that a submicrocrystalline structure developed during ball milling. Tensile tests showed that the material was brittle even up to 300 °C and, therefore, most mechanical tests were carried out under compression. Under those conditions the reinforced material showed yield stresses of 270 MPa at ambient temperature, 170 MPa at 150 °C, and 125 MPa at 300 °C. Mg processed under the same conditions, but without graphite addition, had significantly lower yield stresses. The dispersion‐strengthened Mg showed a marked increase in creep resistance: at 200 °C and a stress, σ c , of 100 MPa, the secondary creep rate, ϵ s , was in the lower 10 –9 s –1 range and at 300 °C and σ c of 80 MPa, ϵ s values of up to 1 × 10 –8 s –1 were measured. The results are discussed.