Development of new pressure vessel with new material for underwater vehicle

We are developing several underwater vehicles. There is development of pressure vessels by new material as one of the element technology to develop underwater vehicles. In the case of electronics to use underwater, defer from when they used in the land, they need solid pressure vessels. The reason is because it has to protect electronics from water and water pressure. Particularly, water pressure is increasing according to depth, so the pressure vessels need to make strong. But strong vessels are very heavy weight. It is not good at treatment. Especially, a heavy pressure vessel makes energy efficiency worse for a deep and long cruising type vehicle. So we started research and development of magnesium alloy to apply as a new structure material to lighten of pressure vessels. Our development target is stronger than Titanium alloy (Ti-6A1-4V) of ratio strength (tensile strength/specific gravity) as strength of a pressure vessel. The Ti-6A1-4V is usually used lightweight and strong material for pressure vessel. In this paper, we report several results of estimation tests. We carried out estimation test about test pieces. And we made a small pressure vessel and carried out estimation tests about strength about this pressure vessel.