Direct laser deposition of alloys from elemental powder blends

The complexity in design of components used in advanced aerospace and autom otive applications is continuously increasing. This has led to the developm ent of near-net shape manufacturing techniques such as laser engineered net -shaping (LENS (TM)) which falls in the class of direct laser deposition pr ocesses-from powder feedstock. Despite considerable advances in process opt imization, there is a rather limited understanding of the role of metallurg ical factors in laser deposition of alloys. This paper discusses the signif icant role played by the thermodynamic enthalpy of mixing in the deposition of alloys from elemental powder blends using LENS (TM). This factor influe nces the homogeneity as well as the rate of solidification of the alloy and consequently the microstructure and properties of the deposit. The enthalp y of mixing could also serve as a very useful guideline in the design of no vel alloys that are laser deposited from elemental powder blends. (C) 2001 Published by Elsevier Science Ltd. on behalf of Acta Materialia Inc.