Material Characterisation of the Turkana Abarait

In this paper, we research the material, mechanical, geometrical and chemical characteristics of the Turkana Abarait, a wrist blade used ubiquitously by Turkana tribesmen and tribeswomen in northwestern Kenya. To characterise the blades, we used a combination of 3D scanning, scanning electron microscopy (SEM) coupled with Image Analysis techniques, X-ray diffraction (XRD), X-ray fluorescence (XRF), and Vickers hardness testing at HV30. We find that the blades are made from low-carbon bloomery iron, containing particulates of slag inclusions, or soot based remnants, as well as trace elements of magnesium, sodium, aluminium, sulphur, phosphorus, chlorine, cobalt, and potassium. While the soot particulates are likely derived from the incomplete refinement and non-uniform heating typical of pre-industrial forging methods, we deduce that the other trace elements originate from irons smelted from riverbed ore. We find that while blade edge angle does not differ between the blades (p > 0.05), the blade edge widths are significantly different (p < 0.001), indicating inconsistencies in the manufacturing processes. We find that there are mechanically significant differences in both inter-and intra-blade hardness values (p < 0.001), adding to our proposition that Abarait blades are manufactured inconsistently. The blades are nevertheless fit for purpose, achieving a balance of hardness and ductility suited to their dual role as cutting tools and close-combat weapons.