AISI 4340 and AISI 4140 are normally used for different structural applications in quenched and tempered state due to their high strength. high abrasion and fatigue resistance but they lack toughness. Presence of dual phase microstructure such as ferrite-bainite and ferrite-martensite in steels have been reported to improve toughness but at the cost of strength. It is believed that de... https://www.graphikjunkie.com/product-category/time-release-dispensers/