Search results
Results from the WOW.Com Content Network
Precipitation hardening relies on changes in solid solubility with temperature to produce fine particles of an impurity phase, which impede the movement of dislocations, or defects in a crystal's lattice. Since dislocations are often the dominant carriers of plasticity, this serves to harden the material. The impurities play the same role as ...
Case hardening is a thermochemical diffusion process in which an alloying element, most commonly carbon or nitrogen, diffuses into the surface of a monolithic metal. The resulting interstitial solid solution is harder than the base material, which improves wear resistance without sacrificing toughness.
Cold hardening is a process in which a plant undergoes physiological changes to avoid, or mitigate cellular injuries caused by sub-zero temperatures. [1] Non-acclimatized individuals can survive −5 °C, while an acclimatized individual in the same species can survive −30 °C.
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 cause resistance to slip dislocations. This is achieved by first heating the metal ...
Precipitation hardening: precipitating a second phase out of the primary lattice blocks dislocation motion. Grain size: increasing grain size decreases the amount of grain boundaries, which results in slower creep due to the high diffusion rate along grain boundaries.
Tempering is a process of heat treating, which is used to increase the toughness of iron-based alloys. Tempering is usually performed after hardening, to reduce some of the excess hardness, and is done by heating the metal to some temperature below the critical point for a certain period of time, then allowing it to cool in still air. The exact ...
These particles are typically larger than those in the Orowon precipitation hardening discussed above. The effect of dispersion strengthening is effective at high temperatures whereas precipitation strengthening from heat treatments are typically limited to temperatures much lower than the melting temperature of the material. [7]
Hardening is the process by which something becomes harder or is made harder. Hardening may refer to: Hardening (metallurgy), a process used to increase the hardness of a metal; Hardening (botany) or cold hardening, a process in which a plant undergoes physiological changes to mitigate damage from cold temperatures