Selective Laser Melting (SLM) is one of the main Additive Manufacturing (AM) technologies for metals, which allows engineers to automatically and flexibly produce directly from a Computer-Aided Design (CAD) model lightweight components with complicated shapes and architectures, that could not be produced by conventional manufacturing processes. One of the most interesting opportunities offered by such technology is the production of lattice structures, which are architected material formed by an array of unit cells regularly repeated in all directions. Such structures possess many superior properties with respect to conventional structures, and moreover they are able to integrate more than one function into a physical part, which makes them attractive for a consistent range of applications. In this thesis work are assessed the mechanical properties of Ti6Al4V lattice structures produced via SLM. First, the main metal AM technologies and the properties and characteristics of the titanium alloys are reviewed. Then, it is discussed the importance of the powder analysis for the powder bed fusion processes. Moreover, the mechanical performances and the manufacturability of thick and thin parts manufactured by SLM are investigated, accounting also for the influence of the orientation of the part and of its position on the building platform. Finally, three different Ti6Al4V lattice structures are designed, printed and mechanically tested to evaluate their static properties and their failure modes.
Selective Laser Melting (SLM) è una delle più diffuse tecnologie di produzione additiva per la lavorazione di metalli, la quale permette di generare direttamente da un modello CAD (Computer-Aided Design) ed in modo flessibile e automatico componenti leggeri caratterizzati da forme e architetture complesse, che non sarebbe possibile ottenere utilizzando i metodi di produzione convenzionali. Una delle opportunità più interessanti offerte da questa tecnologia è la produzione di strutture trabecolari, ovvero materiali con architettura costituiti dalla ripetizione regolare di celle unitarie nelle tre dimensioni spaziali. Queste strutture possiedono diverse proprietà superiori rispetto alle strutture convenzionali, ed inoltre offrono la possibilità di integrare più di una funzione in un unico componente, il che le rende attrattive per un numero consistente di applicazioni. In questa tesi sono valutate le proprietà meccaniche di strutture trabecolari in lega di titanio Ti6Al4V prodotte tramite SLM. Per prima cosa, sono revisionate le principali tecniche di produzione additiva per i metalli e le proprietà delle leghe di titanio. Dopodiché, viene discussa l’importanza dell’analisi delle caratteristiche della polvere per i processi additivi di fusione su letto di polvere. Inoltre, vengono indagate le proprietà meccaniche e la producibilità di parti spesse e sottili prodotte tramite SLM, tenendo in considerazione anche dell’effetto dell’orientazione della parte e della sua posizione sulla piattaforma di stampa. Infine, tre diverse strutture trabecolari in lega di titanio Ti6Al4V sono progettate, prodotte e testate meccanicamente per valutare le loro proprietà meccaniche statiche e i loro modi di cedimento.
Mechanical properties of Ti6Al4V lattice structures manufactured by SLM technology
CALANDRINO, LUCA
2018/2019
Abstract
Selective Laser Melting (SLM) is one of the main Additive Manufacturing (AM) technologies for metals, which allows engineers to automatically and flexibly produce directly from a Computer-Aided Design (CAD) model lightweight components with complicated shapes and architectures, that could not be produced by conventional manufacturing processes. One of the most interesting opportunities offered by such technology is the production of lattice structures, which are architected material formed by an array of unit cells regularly repeated in all directions. Such structures possess many superior properties with respect to conventional structures, and moreover they are able to integrate more than one function into a physical part, which makes them attractive for a consistent range of applications. In this thesis work are assessed the mechanical properties of Ti6Al4V lattice structures produced via SLM. First, the main metal AM technologies and the properties and characteristics of the titanium alloys are reviewed. Then, it is discussed the importance of the powder analysis for the powder bed fusion processes. Moreover, the mechanical performances and the manufacturability of thick and thin parts manufactured by SLM are investigated, accounting also for the influence of the orientation of the part and of its position on the building platform. Finally, three different Ti6Al4V lattice structures are designed, printed and mechanically tested to evaluate their static properties and their failure modes.File | Dimensione | Formato | |
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https://hdl.handle.net/10589/148368