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Target hardening, also referred to simply as hardening when made clear by the context, is a term used by police officers, those working in security, and the military referring to the strengthening of the security of a building or installation in order to protect it in the event of attack or reduce the risk of theft.
In solution hardening, the alloying element does not precipitate from solution. Precipitation hardening (also called age hardening ) is a process where a second phase that begins in solid solution with the matrix metal is precipitated out of solution with the metal as it is quenched, leaving particles of that phase distributed throughout to ...
For this strengthening mechanism, solute atoms of one element are added to another, resulting in either substitutional or interstitial point defects in the crystal (see Figure on the right). The solute atoms cause lattice distortions that impede dislocation motion, increasing the yield stress of the material. Solute atoms have stress fields ...
The Goldschmidt classification, [1] [2] developed by Victor Goldschmidt (1888–1947), is a geochemical classification which groups the chemical elements within the Earth according to their preferred host phases into lithophile (rock-loving), siderophile (iron-loving), chalcophile (sulfide ore-loving or chalcogen-loving), and atmophile (gas-loving) or volatile (the element, or a compound in ...
This hostile vehicle mitigation is a common form of target hardening and is designed to prevent a vehicle being rammed into the building or into people on the pavement next to the building. It also enforces a zone of protective stand-off from any explosive detonation location.
The intent was to induce age-hardening with the aforementioned intermetallics in an iron-nickel martensitic matrix, and it was discovered that Co and Mo complement each other very well. Commercial production started in December 1960. [3] A rise in the price of Co in the late 1970s led to cobalt-free maraging steels. [4]
The definition of which elements belong to this group differs. The most common definition includes five elements: two of the fifth period (niobium and molybdenum) and three of the sixth period (tantalum, tungsten, and rhenium). They all share some properties, including a melting point above 2000 °C and high hardness at room temperature. They ...
Precipitation-hardening alloys first came into use during the early 1900s. Most heat-treatable alloys fall into the category of precipitation-hardening alloys, including alloys of aluminum, magnesium, titanium, and nickel. Several high-alloy steels are also precipitation-hardening alloys. These alloys become softer than normal when quenched and ...