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Materials for Tissue Engineering
Published in Joseph W. Freeman, Debabrata Banerjee, Building Tissues, 2018
Joseph W. Freeman, Debabrata Banerjee
Strain hardening, or work hardening, is the process of making a ductile metal harder and stronger as it is plastically deformed. The temperature at which deformation takes place is “cold” relative to the absolute melting temperature of the metal. This is called cold working. It is sometimes convenient to express the degree of plastic deformation as the percentage of cold work (%CW). It is defined as: %CW=Ao−AdAo×100
Force-System Resultants and Equilibrium
Published in Richard C. Dorf, The Engineering Handbook, 2018
Hot working of metal alloys is normally the next step in the shaping of the cast alloy into a component, and is also used to induce some refinement of the grain structure of the material to obtain the necessary ductility or strength. In hot working, the temperature is high enough that recrystallization occurs at a rate faster than work hardening due to deformation. Forging, rolling, and extrusion are some examples of hot-working processes.
Product Liability
Published in William H. Middendorf, Richard H. Engelmann, Design of Devices and Systems, 2017
William H. Middendorf, Richard H. Engelmann
Another easy-to-overlook aspect of product life is the physical changes that take place in the materials that compose the product due to normal use and environment. A case in point is that of a farmer who suffered the loss of one eye when a piece of metal chipped off a hammer he was using. The hammer was a forged-head carpenter’s hammer; it was being used to drive a pin into a clevis to connect a manure spreader to a tractor. Both sides agreed that there were no metallurgical flaws in the hammer when it left the manufacturer. However, a process known as work hardening occurs whenever metal is squeezed, struck, or bent. Also, it was agreed that as metal hardens it is more likely to break into chips when striking an object harder than itself. At the time of the accident, the hammer had work hardened to a Rockwell hardness of C-52, while the clevis pin had a hardness of C-57. Thus, the mere use of the hammer and the coincidence of the clevis pin being harder than the hammer formed the necessary conditions for an accident to occur.
An investigation on machinability assessment of Al-6XN and AISI 316 alloys: an assessment study of machining
Published in Machining Science and Technology, 2019
Mohanad Alabdullah, Ashwin Polishetty, Junior Nomani, Guy Littlefair
Micro-hardness values in the work-hardening layers were measured using a Vickers instrument in order to locate the work hardening region and work hardening tendency. Struers Vickers hardness tester machine was utilized to conduct this work hardening experiment. The experiment was performed in an advanced machining lab located at Deakin University, Australia. Eight samples for the eight cutting trials were extracted from each alloy. These samples were hot mounted (with the cross section facing up), fine grinded and polished up to 1 mm to remove dirt and to avoid errors in the results as much as possible. Each sample was attached to the instrument and the micro-hardness values recorded under a 0.2HV load. Three readings were selected in the X-axis and a 5 mm step was preferred in the Y-axis, as shown in the sketched Figure 4.
Precipitation strengthening in Mg-Sn alloys with multiple precipitate types
Published in Philosophical Magazine, 2022
Yang Lyu, Ian P. Jones, Yu-Lung Chiu
Work hardening is the increase in strength of metal due to blocking or cross slipping of dislocations preventing further dislocation motion [42]. For a precipitate strengthened alloy, the work hardening will be related to its precipitates. Assuming precipitates do not exist in the alloy, dislocations may glide freely within the alloys in groups and eliminate on the sample surface forming slip bands. With the existence of precipitates, the leading dislocations will be stopped at the precipitates which serve as a barrier. Therefore, succeeding dislocations will then pile up behind the leading dislocations and result in work hardening [43].
Dislocation density evolution and hardening mechanism of AA7050-T7451 surface layer based on anisotropy
Published in Machining Science and Technology, 2023
Zhenda Wang, Yongzhi Pan, Hui Wang, Zewen Zhang, Xiuli Fu, Xiuhua Men
Work hardening is essentially the plastic deformation of a material. Dislocation is the most basic plastic shear unit of plastic deformation. The micro-forming mechanism of work-hardening behavior can be obtained by exploring the evolution law of dislocation behavior.