Laser-assisted combinatorial methods for rapid design of wear resistant iron alloys

Combinatorial design methods require the creation of large libraries of materials with varying composition. These libraries are screened for the desired properties, using rapid micro characterization techniques in order to find the most promising compositions for scale-up and final evaluation. These methods are particularly adequate for the systematic scrutiny of complex systems, aiming to find new materials with outstanding properties for particular applications, but they can also be used in the investigation of structure–properties relationships, alloying behaviour studies and phase diagram determination. Up till now, the application of combinatorial methods to the design of tribological materials has been constrained because, since material library preparation is usually carried out by thin film deposition techniques, the sample size is too small for microstructure-dependent properties to be reliably assessed, and no suitable screening tests are available. In the present paper a novel approach to the combinatorial design of abrasion resistant materials, where laser cladding with computer controlled variable powder feed rate is used to synthesize the material libraries and screening is based on microscratching tests is demonstrated. This method was applied to the optimization of the composition of alloys of the Fe–Cr–C system for abrasive wear resistance.