Friction stir spot welding of aluminum alloys

Deep drawing of conical and spherical thin parts utilizing a rubber punch

Material flow behaviour in the Friction Stir Spot Welding of aluminum alloys

Friction stir spot welding (FSSW) is a technological process that it allows to obtain junctions characterized by good mechanical properties and to perform them in a simple and fast way. The detailed knowledge of material flow around rotating tool, and of the microstructural evolution occurring during this process, constitute the fundamental input to realize analysis and simulation models in order to determine a optimal tool design and high structural efficiency welds. In the present research, an integrated mechanical-metallurgical-morphological analysis has been performer, to evaluate the influence of the different technological parameters on the characteristics of the joint. The experiment…

Spot friction stir welding of aluminum alloys

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Numerical Model for Shape Memory Alloy Actuators

In order to realize a control system for Shape Memory Alloy (SMA) actuators, that ensure high displacement precisions, a numerical model that simulates SMA wire behavior subjected to thermo-mechanical actions, up to high number of cycles, has been set up. In particular, the constitutive model of Brinson, 1993,[1] coupled by a suitable kinetic low has been used. Beginning from such model, some corrections have been performed to take into account the deviations, in term of characteristic temperatures and mechanical responds, due to a numerous thermo-mechanical cycles. Furthermore, in order to complete and check the numerical model, experimental tests have been performed; initially the employe…

Thermo-Mechanical Characterization of Ni-Rich NiTi Shape Memory Alloy

MICROSTRUCTURAL CHARACTERISAZTION OF THERMO-MECHANICAL TREATED TRIP STEELS

The increasing demand for the reduction of automobiles CO2 emissions for environmental preservation leads the automotive industries towards the mechanical components weight reduction. Sheet steels with multiphase microstructures exhibit favourable combinations of strength and ductility. The so called TRIP steels have a metastable microstructure that consists of a continuous ferrite matrix containing a dispersion of hard second phases martensite and bainite. These steels also contain retained austenite, at room temperature, that represents the source of the TRansformation Induced Plasticity effect. When the material is subjected to deformation step, the retained austenite transforms itself i…

Effect of intercritical annealing and of isothermal bainite treatment on microstructure, mechanical and bake hardening properties of TRIP 800 steel

New Characterization Methodology For Shape Memory Alloys

Thermal and thermo-mechanical treatments on shape memory alloys

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Process parameters and surface treatment effects on the mechanical and corrosion resistance properties of Ti6Al4V components produced by laser powder bed fusion

Laser powder bed fusion is one of the additive manufacturing technologies which has developed more rapidly in recent years as it enables the production of very complex geometries. Titanium alloys are among the most popular materials in the aerospace industry thanks to excellent mechanical and corrosion resistance. The corrosion behavior and mechanical properties of samples made of Ti6Al4V and characterized by the geometrical features typical of brackets were investigated taking into account the effects of process parameters on porosity and microstructure. A comparison between the corrosion resistance of samples with complex geometry (3D) and specimens characterized by simple geometry (FLAT)…

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Multi-Layer Neural Network Application For Optimization of Thixotropic Aluminum Alloy Process Parameters

Thermo-mechanical treatments on aluminum alloys for microstructure improvements

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A new control parameter to predict micro-warping-induced job failure in LPBF of TI6AL4V titanium alloy

Abstract Laser powder bed fusion (LPBF) includes a few printing techniques widely used, in recent years, concerning the additive manufacturing of Ti6Al4V alloys. These produced parts, typically utilized in sectors such as aerospace and biomedical, are characterized by very high added value. It is therefore fundamental to identify the influence of process parameters typical of LPBF technology on the occurrence of warping leading to process failure. This study deals with the characterization of single-track and “micro-scale” level warping phenomena which may lead to protrusion of material over the powder bed and process failure before normal termination. This phenomenon was investigated as a …

Effect of Plastic Hot Deformation on the Microstructure of 22MnB5 Microalloyed Boron Steel