On April 22, 1978, the Severodvinsk Shipyard in the port city of Arkhangelsk Oblast, located in the northern part of Russia and Europe, began to build a mysterious new M-class strategic attack nuclear submarine.

Code name: fin

NATO code name: Mike-class

Model: 685

Navy Number: K278

Boat name: member of the Communist Youth League

Water displacement: 5880 tons

Submarine displacement: 8,500 tons

Water draft: 8-9 meters

Length: 117.5 meters

Overall width: 10.7 meters

Power system: 1 190 MW K-650 b-3 pressurized water reactor, 2 45,000 horsepower steam turbines

Fuel: Uranium-235

Water speed: 14 knots

Endurance: nuclear endurance

Self-sustaining power: 50 days

Crew: 69 people

Equipment: 6 torpedoes 533 mm, equipped with 53-65/53-65k torpedoes, missile RPK-2 anti-ship missile

The boat is designed with a double-layer shell structure, and the submarine shell is made by creatively adding the rarefied and refractory metal "rhenium" to the "space metal" titanium alloy. The emergence of the K278 strategic nuclear submarine once again demonstrated to the world the manufacturing capabilities of the "combat nation" in the military industry. At that time, in order to produce the world's strongest strategic nuclear submarine, the former Soviet Union did not hesitate to pay for it. It is important to know that the annual output of the global metal rhenium at that time was only one to twenty tons.

This nuclear submarine can withstand the huge pressure of sea water at a depth of more than 1,000 meters, which is equivalent to more than 100 standard atmospheres. The maximum maximum diving depth is an astonishing 1250 meters, and the US military deep-water torpedo at the time was only 800 meters deep.

It is conceivable that such a super weapon has extremely high survivability in the deep sea. However, on April 7, 1989, after nearly 6 years of service, the submarine "Komsomol" sank due to a fire accident. The Balun Sea of the Arctic Ocean is an icy seabed of 1685 meters at 73°40ˊ north latitude and 13°30ˊ east longitude. The accident resulted in the death of 42 crew members, including Captain Vanin, and 27 people were rescued. It is a pity that such a deep-sea monster has only produced one, but the world record for the deepest dive of a strategic attack nuclear submarine created by it is still maintained to this day.

The extreme service environment of the "deep sea monster" puts forward demanding limit requirements for many materials, among which the creative application of titanium rhenium alloy provides inspiration for future materials science experts. The lightweight, high-strength, and corrosion-resistant characteristics of the metal "titanium", and the super strengthening effect of the battle metal "rhenium" added to the alloy, can't be more beautiful with the term "adding wings" to describe this new material. It is believed that in many other fields of science and technology in the future, such as low-altitude aircraft, super high-speed rail, aviation, aerospace, deep-sea exploration, etc., titanium rhenium alloy will receive more and more attention and development and application.