[1] Vaal Univ Technol, Dept Met Engn, Andries Potgieter Blvd, ZA-1911 Vanderbijlpark, South Africa
[2] CSIR, Adv Mat & Engn, Mfg Cluster, Pretoria, South Africa
[3] Univ Johannesburg, Sch Min Met & Chem Engn, Johannesburg, South Africa
[4] Tshwane Univ Technol, Inst NanoEngn Res, Dept Chem Met & Mat Engn, Pretoria, South Africa
[5] Natl Inst Mat Sci, Sengen 1-2-1, Tsukuba, Ibaraki 3050047, Japan