Nanostructured laminar tungsten alloy with improved ductility by surface mechanical attrition treatment.

A nanostructured laminar W-LaO alloy (WL10) with improved ductility was prepared using a surface mechanical attrition treatment (SMAT). φ1.5 mm ZrO WL10 balls subjected to SMAT (called φ1.5 mm ZrO ball SMATed WL10) samples possess the best surface profile and excellent integrated mechanical properties (the ductile-brittle transition temperature (DBTT) value decreases by approximately 200 °C, and the bending strength decreases by 100 Mpa). A highly dense group of laminates was detected near the surface of the φ1.5 mm ZrO ball SMATed WL10 sample. The SMATed WL10 laminates were composed of a micro-grain layer, an ultrafine-grain layer and a nanosized-grain layer. The nanostructured laminar surface layer of the φ1.5 mm ZrO ball SMATed WL10 sample is approximately 1-2 μm. The top surface of the WL10 plates with and without the SMAT process possesses residual compressive stress of approximately -883 MPa and -241 MPa, respectively, in the y direction and -859 MPa and -854 MPa, respectively, in the x direction. The SMAT process could be a complementary method to further improve the toughness of tungsten-based materials.