The reason that an iceberg is able to cut into the side hull of a ship (e.g. Titanic etc.) or any other marine vessel is dual fold. The first reason is because steel becomes more brittle, the colder it gets. Steel created during the early 20th century was not tempered as steel is during the modern day. The second reason is because of inertia, weight, and force. An iceberg can slash through steel the same way a tree can rip through a vehicle that has hit it. An iceberg is a large, immovable object, so whether the hull is comprised of wood or titanium, the ice will always win out as it has more inertia and mass. To provide a frame of reference, bone is incredibly strong and tensile, however if a brick which is harmless while at rest, slams down from a height above the arm, the force it imparts is enough to break said bone
Damascus, Syria, the birthplace of Damascus steel was prized in the ancient world for its durability but unbeknownst to the craftspeople who forged Damascus steel, the region from which the iron ore was taken had naturally occurring nickel which meant that Damascus metalsmiths had composite steel 3000 years before the rest of the world as the idea to mix different kinds of metals had not yet been invented. Damascus steel was shatter resistant and could be sharpened to become sharper than any other type of steel. Having first encountered it during the Crusades of the 11th century, European forgers attempted for centuries to recreate what their Middle Eastern counterparts had already perfected