It is stated in learned reports that elements of design should link all of the engineering courses that are taught at a degree level. Engineering courses are, however, significantly different from materials science courses, in terms of goals and the nature of the students that they attract. Most of the research on design has focussed on the engineering subject, sometimes with derisory comments about materials science and in general about the role of science in engineering. It is necessary therefore to have a look at design from the point of view of materials science, which is after all the more interdisciplinary than engineering or the more common natural sciences. This could be a major advantage as far as design is concerned; in particular, a well trained materials scientist should be able to communicate effectively with technologists and scientists alike.There are some obvious aspects of materials science in which an element of creative design may be useful. We may often be called upon to design experiments either to rank new materials or to develop them. The current trend in the highly competitive aircraft industry is to reduce the time taken from the point where a new engine or airframe is conceived to its manufacture and certification. Well designed experiments are therefore necessary to ensure that materials, which can make or break particular manufacturers, do not form the rate limiting stage. It is rare indeed to find an undergraduate materials course in which the design of an experiment is the core of a practical class; the normal way is for students to perform tried and tested scripts.
And it is not difficult to distinguish between a craftful experiment and one which is based on brute force. For example, in cases where a tensile stress affects transformation, most reported experiments have involved the manufacture of a series of parallel gauge length tensile specimens, which are then tested at different loads, so that the resulting microstructure can be correlated against a number of discrete values of applied stress. On the other hand, a single tensile specimen with a slightly tapered gauge length could be pulled to failure. Continuous information is thus obtained, from a single test, of the influence of stress (yield to failure) on microstructure. It is probable that materials scientists are more involved in the design of experiments than their engineering colleagues.
Materials scientists often play a key role in the making of new manufacturing processes, usually as a part of a team. The subject is already taught widely in a variety of guises - for example, most materials undergraduates at some stage do a comparative study of ingot and continuous casting. Case studies like these are important, but on their own, probably not sufficient to inspire thinking in all but the best of students. For that it is necessary to present an unsolved problem. For example, any realist would argue that there are many outstanding and serious problems with the use of aluminium in the mass production of car bodies. Price, of course, is one of the major factors. Those in the know will tell you that a more energy efficient process than electrolysis is required in order to extract aluminium from the ore. Smelting is a serious though unestablished alternative and it would be educational and interesting to consider the design of such a process, taking into account thermodynamic, economical and capital cost factors. Such an exercise would also involve a survey of existing literature.
The design of materials per se is probably already a major component of current degree courses - alloy design (using quantum mechanical to microstructural techniques), the molecular design of polymers, the fabrication of ceramics, designer glasses and composite manufacture are all familiar and important buzz words. What appears to be lacking, is an ability to analyse what could be done once a new material is invented. I know of one example in the steel industry where successful research has led to the manufacture of what could be a revolutionary steel for rail applications. Whereas the academic partner of this work was satisfied with the success, the industrial partner had the vision to institute a series of studies involving wear resistant materials in a number of applications which have nothing to do with railways.
It is difficult to see how students could be involved in a good, exciting exercise on the design of a novel structure or component. In industry, projects like these are carried out by large teams consisting of many disciplines. For example, to design a novel geometry for steel beams of the type used in the construction of multistorey buildings, requires wide ranging expertise. Structural engineers are able to analyse for stability to buckling under a variety of complex loads, and to advise on safety factors. The knowledge of fire engineers is necessary in order to ensure, as the standards require, that the building does not collapse within a specified period of time, due to a loss of strength in the steel as it is heated by the fire. Rolling technologists have to make the actual sections from standard ingot shapes - they may insist that their machines cannot cope with highly assymetrical shapes without large scale capital investment. Finite element modellers may predict whether it is possible even in principle to roll certain shapes while at the same time ensuring uniform properties. Metallurgists are required both to test any new sections and to develop steels designed to transform to uniform microstructures on cooling, in spite of non-uniform deformations encountered during rolling. Accountants are essential to cost the research, to trek the costs during the project, and to indicate the level of beneficial change that is necessary before it becomes viable to invest in a new manufacturing process. Market research plays a key role in such a venture. Most degree courses do not have the resources, especially in terms of time, to support such an approach. The practical suggested earlier is in this sense a feeble attempt. Role play on the scale of an entire class may be an approach worth trying.
Many undergraduate courses involve the study of artifacts in the form of a manufactured article. The students are required to disassemble a component, examine the materials using a variety of techniques, and then make some recommendations on how the component might be manufactured better. The difficulty with such exercises is that the subject of materials science is now so broad, that there is a distinct lack of depth in what is taught. Students are therefore not sufficiently capable of systematically investigating the complex industrial materials present in commercial components. Because such components are usually well manufactured and designed (otherwise they probably would not be available) there is little, within the scope of their knowledge, that students can do to suggest realistic improvements. Artifact based projects have therefore become less interesting to students.
Some ways in which creative design is, or may be incorporated in the materials science degree curriculum are presented in Table~1. I believe that both conventional and unconventional approaches can be pepped up using the rules described earlier. It should be obvious that the task is not simple, and that time and other resources would have to be diverted from other aspects of teaching and learning. But the subject is certainly useful, challenging and worthy of further discussion.
CONVENTIONAL UNCONVENTIONAL Practical Inter-departmental project Examples class Inter-university project Literature survey Market research Case study Industrially organised brainstorming Research project Student originated research project Industrially based project Involvement in real industrial design Investigation of artifact Real failure investigation Computer-aided design Software design Selection exercise Role play Table 1: Possible routes for the teaching of design in materials science
The features which make the teaching of design distinctive can be summarised as follows:
These rules and the general concepts propounded by Woody Flowers are now illustrated with two specific cases for Materials Science. The first is a practical class which is attempted by students in teams of three or four. The second is an "examples class" in which students can work in small groups or as individuals. These cases are stated in a form suitable for presentation to students.
The practical class in particular encourages team effort. The group have to produce a single report, with each member of the team getting the same mark after assessment. It also mirrors the sort of situation which might arise in industry, where a market manager sets a task and a deadline without giving expert guidance. As in industry, there is limited access to a consultant. Efficiency and cost are also featured.