Part B questions AY 2022 23

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Dep ar tment of Mechanical Engineering Applied Met allurgy: P ar t B Questions Author: Fabio Santoro Advisor: Prof. Fabrizio D’Errico Academic year: 2022-2023 Abstract: This article contains the possible answers to the questions that can be assigned to the Part B of the exam of Applied Metallurgy Contents 1 Discuss the phenomena of damage in metallic materials related to the phenomenon of: brittleness 3 2 Discuss the phenomena of damage in metallic materials related to the phenomenon of: fatigue 6 3 The surface treatments for the hardening of steels and the phenomenon of contact fatigue 9 4 The phenomenon of damage due to corrosion of metals and the choice of stainless steels for counteracting this phenomenon 13 5 The phenomenon of damage due to wear and the choice of tool steels for counter- acting this phenomenon 17 6 The phenomenon of creep and the choice of special steels for using at high temper- atures 21 7 Magnesium Alloys 25 8 Titanium alloys 28 9 Steels for special applications (Specialty Steels): HSLA, TRIP and Dual Phase steels 31 10 The steel making processes 34 11 Aluminum alloys and main casting processes 37 this page left 1 Discuss the phenomena of damage in metallic materials related to the phenomenon of: brittleness A metallic material is characterized by a regular structure named crystal structure. The crystal structure is composed by the repetition of elementary (or unit) cells. However the real crystal lattice is not perfect and it presents defects (can be vacancies, interstitial atoms, substitutional atoms, angle of misalignment at grain boundaries and dislocations. In particular, dislocations determine the capability of a material to be plastically deformed (with macroscopic effects). This property distinguishes two main categories of metallic…