DEVELOPMENT OF RHEO-DIECASTING (RDC) PROCESS FOR PRODUCTION OF HIGH INTEGRITY COMPONENTS

摘要

Rheo-diecasting (RDC) is an innovative one-step semisolid metal (SSM) processing technique to manufacture near net shape components of high integrity directly from liquid alloys. The RDC process innovatively adapts the well-established high shear dispersive mixing action of a twin-screw mechanism for in situ creation of SSM slurry with fine and spherical solid followed by direct shaping of the SSM slurry into near-net shape components using cold chamber high pressure diecasting (HPDC) process. Based on the results achieved so far, RDC shows several advantages over conventional HPDC process such as, finer and more uniform microstructure, close to zero porosity, more tolerant to inclusions, ability to process a wider range of alloys, and improved mechanical properties. In this paper, we report the rheo-diecasting process and the scientific understandings behind this technological development We also present the microstructures and mechanical properties of various Al- and Mg-alloys processed by RDC.