Summer and the Holidays are here. It is a time to slow down, just a little. However, at times like this I have the luxury of "what iffing". At such times, I reflect back to what the world seemed to be when I was a young engineer. Steel was the material of choice for good reason: it was cheap, it was abundant, and it had the properties of strength and ductility.
Slowly but surely I watched as new elements began to fill the periodic table New, more exotic microscopes emerged that permitted us to observe topography, defects, and even determine phases and chemistry of these phases. Eventually we could strip atoms from surfaces and determine the composition and degradation of protective surfaces, atomic layer by atomic layer. Now equipment is available that permits us to even look within the atom itself. Thermodynamics became important, and for early designs such as cars and aircraft, stainless steels and superalloys emerged, permitting jet aircraft and space vehicles to become possible. Coatings were developed that protected vulnerable surfaces from oxidation, wear and shock. Processes and techniques were developed to shape and join components together to make more sturdy structures for sea worthiness, windmills and nuclear reactors for efficient electrical energy.
However, with the good comes the bad. As more and more of the resources available courtesy of Mother Nature were depleted and processes required for reclamation, purification, fabrication and operation increased, resources required to do these operations resulted in increased pollution of our environment. Therefore we found ourselves seeking alternate materials and processes that would reduce weight, improve efficiency, reduce cost and permit increasing opportunities to make things that were currently not possible.Weight became cost saving in material, time and labor. For example, in many applications, such as turbine blades, expensive superalloys, containing more expensive alloying elements. to provide high temperature properties such as creep resistance, and prevent more reactive corrosion from occurring at the higher temperatures of operation, limitation of usage resulted and expense became burdensome for small gains in material properties.
To alleviate some of these problems, solutions were first pioneered again by the auto and the aircraft industry to further reduce weight by looking for new alloy systems that would have higher strength without sacrifice to ductility. Therefore more interest in titanium, aluminum and magnesium alloys. One way of accomplishing this is through powder metallurgy. It is well known that different tools are available to improve strength of light alloys made from powders. The problem remains how to do this without limitation of ductility.Methods have been developed to atomize fine powders in atmospheres that protect surfaces from contamination, thereby improving densification when consolidated, with improved ductility. New alloy systems are being developed to take advantage of the new processing of powders.In addition, there is new interest in producing more ductile composite powders and ceramics that may have high temperature strength with improved ductility. If this happens then space becomes the new world and transportation becomes faster, providing opportunities not realized to date.
Powders are not limited in the size of a part being produced. For instance, already possible are production of orthodontic devices to improve functions of the mouth. These devices are made possible by recently developed metal injection molding processes. Other medical devices, such as small stents, have served to improve human and animal life. These are small parts. They are expensive, but they cannot be made by currently developed procesess.
However, not so fast, because now new processing has emerged called advanced manufacturing, because it includes several current technology under development. Not only were processes required to produce new undeveloped powders with undefined properties but instruments, such as lasers and electron beam guns were required to deposit the powders in atomic layers quickly, where they are melted and built layer by layer from the smallest conceivable part to an auto body or even a nuclear reactor structural member. These developments are in progress currently. By use of the computer and robots, these structures can be made, small or large, atomic layer by atomic layer with no restriction of geometry. Therefore, thin parts with complex designs not possible before become reality. I could go on, because there is much more to come that is even more mind boggling.
The other buzz word of the day is modeling. This is a new term but an old concept. Back in the 1980s it was known as regression analysis and it came on because hand held computers became available. These permitted storage and saving of information.Today we have aging equipment and processes that have not been maximized for efficiency and precision. Today's technology requires improved efficiency, and in many cases, precision. Through examination of critical variables that could affect the properties, these known, established processes can be fine tuned to yield higher quality functioning parts. Alloy systems and processes can become more efficient, resulting in significant savings.Therefore many well known processes are undergoing modeling studies today to make improved parts at lower cost. Not a new thought--just made faster through use of the computer.
Therefore, to the young materials engineer just starting his or her career,, hang in there. This is still an exciting world with much still to be accomplished. You are that young engineer as I was in days of yore, watching a steel industry and a transportation industry grow. Hey, it just ain't over til the fat lady sings.