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Heat treating is a group of industrial, thermal and metalworking processes used to alter the physical, and sometimes chemical, properties of a material. The most common application is metallurgical. Heat treatments are also used in the manufacture of many other materials, such as glass. Heat treatment involves the use of heating or chilling, normally to extreme temperatures, to achieve the desired result such as hardening or softening of a material. Heat treatment techniques include annealing, case hardening, precipitation strengthening, tempering, carburizing, normalizing and quenching. Although the term heat treatment applies only to processes where the heating and cooling are done for the specific purpose of altering properties intentionally, heating and cooling often occur incidentally during other manufacturing processes such as hot forming or welding.
Austenite, also known as gamma-phase iron (γ-Fe), is a metallic, non-magnetic allotrope of iron or a solid solution of iron with an alloying element. In plain-carbon steel, austenite exists above the critical eutectoid temperature of 1000 K (727 °C); other alloys of steel have different eutectoid temperatures. The austenite allotrope is named after Sir William Chandler Roberts-Austen (1843–1902). It exists at room temperature in some stainless steels due to the presence of nickel stabilizing the austenite at lower temperatures.
Bainite is a plate-like microstructure that forms in steels at temperatures of 125–550 °C. First described by E. S. Davenport and Edgar Bain, it is one of the products that may form when austenite is cooled past a temperature where it is no longer thermodynamically stable with respect to ferrite, cementite, or ferrite and cementite. Davenport and Bain originally described the microstructure as being similar in appearance to tempered martensite.
In metallurgy, a shape-memory alloy (SMA) is an alloy that can be deformed when cold but returns to its pre-deformed ("remembered") shape when heated. It is also known in other names such as memory metal, memory alloy, smart metal, smart alloy, and muscle wire. The "memorized geometry" can be modified by fixating the desired geometry and subjecting it to a thermal treatment, for example a wire can be taught to memorize the shape of a coil spring.
Magnetic shape memory alloys (MSMAs), also called ferromagnetic shape memory alloys (FSMA), are particular shape memory alloys which produce forces and deformations in response to a magnetic field. The thermal shape memory effect has been obtained in these materials, too.
In materials science, quenching is the rapid cooling of a workpiece in water, gas, oil, polymer, air, or other fluids to obtain certain material properties. A type of heat treating, quenching prevents undesired low-temperature processes, such as phase transformations, from occurring. It does this by reducing the window of time during which these undesired reactions are both thermodynamically favorable and kinetically accessible; for instance, quenching can reduce the crystal grain size of both metallic and plastic materials, increasing their hardness.
Maraging steels are steels that are known for possessing superior strength and toughness without losing ductility. Aging refers to the extended heat-treatment process. These steels are a special class of very-low-carbon ultra-high-strength steels that derive their strength not from carbon, but from precipitation of intermetallic compounds. The principal alloying element is 15 to 25 wt% nickel. Secondary alloying elements, which include cobalt, molybdenum and titanium, are added to produce intermetallic precipitates. Original development was carried out on 20 and 25 wt% Ni steels to which small additions of aluminium, titanium, and niobium were made; a rise in the price of cobalt in the late 1970s led to the development of cobalt-free maraging steels.
Technology forecasting attempts to predict the future characteristics of useful technological machines, procedures or techniques. Researchers create technology forecasts based on past experience and current technological developments. Like other forecasts, technology forecasting can be helpful for both public and private organizations to make smart decisions. By analyzing future opportunities and threats, the forecaster can improve decisions in order to achieve maximum benefits. Today, most countries are experiencing huge social and economic changes, which heavily rely on technology development. By analyzing these changes, government and economic institutions could make plans for future developments. However, not all of historical data can be used for technology forecasting, forecasters also need to adopt advanced technology and quantitative modeling from experts’ researches and conclusions.
In metallurgy and materials science, annealing is a heat treatment that alters the physical and sometimes chemical properties of a material to increase its ductility and reduce its hardness, making it more workable. It involves heating a material above its recrystallization temperature, maintaining a suitable temperature for an appropriate amount of time and then cooling.
Pseudoelasticity, sometimes called superelasticity, is an elastic (reversible) response to an applied stress, caused by a phase transformation between the austenitic and martensitic phases of a crystal. It is exhibited in shape-memory alloys.
Nickel titanium, also known as nitinol, is a metal alloy of nickel and titanium, where the two elements are present in roughly equal atomic percentages. Different alloys are named according to the weight percentage of nickel; e.g., nitinol 55 and nitinol 60.
A cryogenic treatment is the process of treating workpieces to cryogenic temperatures in order to remove residual stresses and improve wear resistance in steels and other metal alloys, such as aluminum. In addition to seeking enhanced stress relief and stabilization, or wear resistance, cryogenic treatment is also sought for its ability to improve corrosion resistance by precipitating micro-fine eta carbides, which can be measured before and after in a part using a quantimet.
A diffusionless transformation, commonly known as displacive transformation, denote solid-state alterations in the crystal structure that do not hinge on the diffusion of atoms across extensive distances. Rather, these transformations manifest as a result of synchronized shifts in atomic positions, wherein atoms undergo displacements of distances smaller than the spacing between adjacent atoms, all while preserving their relative arrangement. An exemplar of such a phenomenon is the martensitic transformation, a notable occurrence observed in the context of steel materials. The term "martensite" was originally coined to describe the rigid and finely dispersed constituent that emerges in steels subjected to rapid cooling. Subsequent investigations revealed that materials beyond ferrous alloys, such as non-ferrous alloys and ceramics, can also undergo diffusionless transformations. Consequently, the term "martensite" has evolved to encompass the resultant product arising from such transformations in a more inclusive manner. In the context of diffusionless transformations, a cooperative and homogeneous movement occurs, leading to a modification in the crystal structure during a phase change. These movements are small, usually less than their interatomic distances, and the neighbors of an atom remain close. The systematic movement of large numbers of atoms led to some to refer to these as military transformations in contrast to civilian diffusion-based phase changes, initially by Frederick Charles Frank and John Wyrill Christian.
TRIP steel are a class of high-strength steel alloys typically used in naval and marine applications and in the automotive industry. TRIP stands for "Transformation induced plasticity," which implies a phase transformation in the material, typically when a stress is applied. These alloys are known to possess an outstanding combination of strength and ductility.
Olusegun O. Adewoye (1947–2015) was the director general and chief executive of the National Agency for Science and Engineering Infrastructure (NASENI), Abuja, Nigeria.
The Graduate Institute of Ferrous Technology is an institute for graduate-level education and research in the field of iron and steel technology at Pohang University of Science and Technology, South Korea. It has nine specialized laboratories covering all sides of metallurgy. However, the Institute now has a reduced focus on steels, having introduced laboratories on battery electronics,.
The Singapore University of Technology and Design (SUTD) is a public autonomous university in Singapore.
In materials science, toughening refers to the process of making a material more resistant to the propagation of cracks. When a crack propagates, the associated irreversible work in different materials classes is different. Thus, the most effective toughening mechanisms differ among different materials classes. The crack tip plasticity is important in toughening of metals and long-chain polymers. Ceramics have limited crack tip plasticity and primarily rely on different toughening mechanisms.
The Neoloy Geocell is a Cellular Confinement System (geocell) developed and manufactured by PRS Geo-Technologies Ltd. Geocells are extruded in ultrasonically welded strips. The folded strips are opened on-site to form a 3D honeycomb matrix, which is then filled with granular material. The 3D confinement system is used to stabilize soft subgrade soil and reinforce the subbase and base layers in flexible pavements. Cellular confinement is also used for soil protection and erosion control for slopes, including channels, retention walls, reservoirs and landfills.
Dan J. Thoma is an American metallurgist who is a Professor in the Department of Materials Science and Engineering at the University of Wisconsin–Madison. He is the director of the Grainger Institute for Engineering at the University of Wisconsin–Madison. Thoma is also a past President of the American Institute of Mining, Metallurgical, and Petroleum Engineers (AIME). Thoma is well-known for his research on 3D printing technology, which he has carried out for over two decades.
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- ↑ "Transformation kinetics, microplasticity and aging of martensite in Fe-31Ni".
- ↑ Davies, R. G.; Magee, C. L. (1972). "Microcracking in ferrous martensites". Metallurgical and Materials Transactions B. 3 (1): 307–313. Bibcode:1972MT......3..307D. doi:10.1007/BF02680610. S2CID 94971094.
- ↑ Magee, C.L; Davies, R.G (1971). "The structure, deformation and strength of ferrous martensites". Acta Metallurgica. 19 (4): 345–354. doi:10.1016/0001-6160(71)90102-7.
- ↑ Magee, C. L.; Thornton, P. H. (1978). "Design Considerations in Energy Absorption by Structural Collapse". SAE Transactions. 87: 2041–2055. JSTOR 44611155.
- ↑ Thornton, P. H.; Magee, C. L. (1975). "The Deformation of aluminum foams". Metallurgical Transactions A. 6 (6): 1253–1263. Bibcode:1975MTA.....6.1253T. doi:10.1007/BF02658535. S2CID 137672091.
- ↑ Davies, R. G.; Magee, C. L. (1975). "The Effect of Strain-Rate Upon the Tensile Deformation of Materials". Journal of Engineering Materials and Technology. 97 (2): 151–155. doi:10.1115/1.3443275.
- ↑ Basnet, Subarna; Magee, Christopher L. (2016). "Modeling of technological performance trends using design theory". Design Science. 2. arXiv: 1602.04713 . doi:10.1017/dsj.2016.8. S2CID 7726424.
- ↑ Magee, Christopher L. (2010). "The role of materials innovation in overall technological development". JOM . 62 (3): 20–24. Bibcode:2010JOM....62c..20M. doi:10.1007/s11837-010-0043-5. S2CID 109994355.
- ↑ Woo, JongRoul; Magee, Christopher L. (2017). "Exploring the relationship between technological improvement and innovation diffusion: An empirical test". arXiv: 1704.03597 [q-fin.EC].
- ↑ "Henry Marion Howe Medal". Archived from the original on 2020-10-10. Retrieved 2020-10-07.
- ↑ "William Hunt Eisenman Award".