It was not that many years ago that stainless steels were considered inferior to carbon steels, however it is now recognized that modern crucible steels can perform as well as, if not better than carbon steels.

Different steels are suited to different applications. There is a trade off between toughness, edge retention, hardness,  achievable sharpness and corrosion resistance.

Blade materials are those used to make the blade of a knife or other simple edged hand tool or weapon, such as a hatchet or sword. The blade of a knife can be made from a variety of materials, the most common being  stainless steel, carbon steel, tool steel and alloy steel. Other less common materials used in knife blades include: cobalt and titanium alloys, ceramics, obsidian, and plastic.

Knife and Sword Steel: The 1st humans melted iron objects around 2500 before Christ, but iron does not become a major material till much closer to the 500 before Christ. The earliest iron production took place in Turkey. There is a considerable debate currently on how humans ever found out how to convert iron oxide ores (essentially rust) into usable metal. The Greeks used only limited iron, it was the Celts at the same time frame who were the first culture to be based on iron making weapons and tools. The creation of a workable iron bloom from iron ore was (and still remains) a challenging and resource intensive effort. In the early beginnings of the iron age it was difficult to obtain iron.