Materials Science Forum, Vol.426-4, 4609-4615, 2003
Thermo-mechanical processing improvements: Benefits and costs
Many high performance metallic alloys depend on thermo-mechanical processing to exhibit the level of properties that make them attractive. Among the classes of alloys that fit this description are Ti, Ni and Al alloys. It is therefore, interesting to ask if the properties of these alloys have been optimized with the attendant question: "Can more performance be expected through better control of then-no-mechanical processing". The answer to this question calls into focus the well-known differences between the best properties generated in the laboratory and the so-called "minimum values" that are used in the design of products. It is well known that there is a significant discrepancy between these property values, with design minimums being consistently lower. This suggests that better control of processing can close this gap, resulting in a major benefit. This paper examines this question and suggests some possible means of closing the "gap". In particular, it will be argued that better process modeling will allow the achievement of more uniform properties of complex shaped forgings to be realized. The use of better models will meet some resistance on the basis of cost. It will be argued that the only realistic alternative is significant improvement in process control.
Keywords:thermo-mechanical processing;computational modeling;microstructure;properties;forging;inertia welding;friction stir welding;process window;cost models;performance models