Abstract: A process for heat treating metal workpieces contains with respect to an efficient process control the following successive operations following directly one after the other: a heating phase; an enrichment phase; a first cooling phase; a bonding phase; a second cooling phase; and a concluding quenching phase. Workpieces processed by a method of this type are distinguished by a comparatively great fatigue limit and fatigue strength with simultaneous high resistance to wear and tear.

Abstract: A metal material that is, without using expensive apparatus, carburized in a low temperature region where crystal grains do not grow so much, and a producing method of the metal material are provided. A metal material mainly containing iron, wherein a surface of the metal material is subjected to a carburization treatment by a treatment using fullerenes as a carbon source.

Abstract: The surface hardening diffusion process for an austenitic material such as 300-series stainless steel uses a pack carburization process at a temperature range from about 1500.degree. F. to about 2500.degree. F. for a period of time ranging from about one (1) to about eight (8) hours. Chromium carbides are formed on the surface of the austenitic material for increasing its wear resistance.

Abstract: Disclosed are a Ti--Al alloy including aluminum (Al) in an amount of 30 to 38% by weight, nitrogen (N) in an amount of 0.2 to 1.0% by weight, and titanium (Ti), substantially the balance, and a process for producing the same. Since the Ti--Al alloy includes the nitrogen in the predetermined amount, the microstructure of the Ti--Al alloy can be micro-fined and made into a uniform one, and accordingly the shrinkage cavities can be reduced remarkably. Therefore, the strength, the ductility or the like of the Ti--Al alloy can be improved remarkably. With the production process, it is possible to produce the Ti--Al alloy including the nitrogen in the predetermined range.