Rights:
© 2010 American Physical Society (APS). This is the accepted version of the following article: Picallo, Clara B. & López, Juan M. & Zapperi, Stefano & Alava, Mikko J. 2010. From Brittle to Ductile Fracture in Disordered Materials. Physical Review Letters. Volume 105, Issue 15. 155502/1-4. ISSN 0031-9007 (printed). DOI: 10.1103/physrevlett.105.155502, which has been published in final form at http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.105.155502.