Selective electrochemical machining of the steel molds in hot isostatic pressing of Ti6Al4V powder

Anodic dissolution is proven to be an effective method to remove stainless steel molds from Ti6Al4V compacts obtained from powder by hot isostatic pressing. Two different working solutions were studied: 2 M NaCl and 2 M NaCl + 0.05 M Na2EDTA. While both were capable of removing the steel mold, the latter was also capable of removing the diffusional layer made by the intermetallic phases generated between titanium and steel during the compaction process

Effect of fibre laser marking on surface properties and corrosion resistance of a Fe-Ni-Cr alloy

Fiber laser techniques are increasing their use in many applications, including modification of material surface properties. In particular they are often used for materials' marking as a non-contact processing. In spite of this, the impact of the laser beam on the surface causes metallurgical and morphological changes. The developments during the laser-material interaction can also affect other surface properties, especially corrosion properties which are crucial in the case of Iron-Nickel alloys. Effect of laser marking on a Fe-Cr-Ni alloy using a Tm-fibre laser (IPG Photonics TRL1904; maximum power: 50W, wavelength: 1904 nm), is described in this paper. In order to evaluate the effect of the laser on corrosion properties a specific ageing test in salt spray has been performed. Moreover, superficial morphology analyses have been performed on samples before and after corrosion tests. Possibilities and limitations of laser marking on these alloys have been discussed, in particular from the point of view of the marked surface corrosion resistance preservation

Friction stir welding of AlSi10Mg plates produced by selective laser melting

A preliminary research work is carried out to demonstrate the feasibility of friction stir welding AlSi10Mg plates produced by selective laser melting. The metallurgical evolutions occurring have been studied and discussed on the basis of detailed microstructure observations. The FSW process enhances the structure of the parent material so that the weld presents an overall refinement of the microstructure and a decrease in microporosity in all its zones. Using the friction stir welding technology, sound welds harder than the parent material can be obtained

Form and Dimensional Accuracy of Surfaces Generated by Longitudinal Turning

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Bilateral hypertrophy of masseteric and temporalis muscles, our fifteen patients and review of literature

OBJECTIVE: The association of bilateral hypertrophy of temporalis and masseteric muscles is a rare clinical entity. The origin of the condition is unclear, causing cosmetic problems, pain, and functional impairment. PATIENTS AND METHODS: In this paper we analyzed 15 patients treated at the Department of Maxillo-Facial Surgery of the University of Naples Federico II, from 2000 to 2013, for temporalis and/or masseteric muscle hypertrophy, and in particular, a rare case of a patient with a marked bilateral swelling of the temporalis and masseteric region, in conjunction with a review of the literature. RESULTS: Fourteen patients have not any kind of postoperatively problems. The last patient had been aware of the swelling for many years and complained of recurrent headaches. We adopted a new protocol fort these patients and the patient was very pleased with the treatment resul ts, and reported a reduct ion in headaches and a continuation of his well-being, in addition to greater self-confidence. The last follow-up was performed three years after the first treatment, and the patient showed a complete resolution of his symptoms, and just a small increase of the swelling. CONCLUSIONS: The treatment of temporalis and masseteric hypertrophy with Botulin toxin could be an effective option compared to conservative treatment or surgical intervention although the review of the literature shows that this is only a temporary treatment. In fact, surgery still remains the best option. The treatment must be repeated every 4/6 months for 2-3 consecutive years before having stable benefits. To overcome this problem, an association with a bite treatment allowed us to achieve more lasting and more stable results over time without a recurrence of symptoms between the treatments. Furthermore, this association has enabled us to obtain a more rapid reduction of the hypertrophy

Beta Forging of a Ti6Al4V Component for Aeronautic Applications: Microstructure Evolution

Ti–6Al–4V is an alloy increasingly used for structural applications in aeronautics due to its characteristics of high mechanical properties, lightness, and corrosion resistance. This alloy is conventionally forged below the beta transus temperature in order to control the microstructure evolution, to obtain a component with the desired properties. In this paper, some experiences of an innovative beta forging process of the Ti–6Al–4V alloy are reported. A preliminary campaign of forging tests in the beta field on cylindrical coupons was carried out in order to study the microstructural evolution in different forging conditions, in terms of both temperature and strain rate. Moreover, in order to study the microstructural evolution due to the beta forging in a complex shaped component, a case study is presented. The forged component showed a microstructure coherent with the forging process experienced; moreover, the hardness values measured were similar to the ones of the Ti–6Al–4V alloy in mill-annealed conditions

Form and dimensional accuracy of surfaces generated by longitudinal turning

The influence of the dynamic behaviour of the machine tool/workpiece system on the surface accuracy plays an important role in finish machining. In particular, the machine tool/workpiece dynamics determines the topography of the machined surface, which is crucial in determining the quality and performance of a mechanical part. A model to predict the dynamic effects of the cutting process in turning, as part of a machining simulation framework, is presented in this paper. Thermally, kinematically and dynamically induced errors can be easily implemented into the proposed model. Finally, several examples of the use of this model under different turning conditions are presented and compared to typical machined surfaces. The proposed model can effectively compute the roughness, form and dimensional accuracy of a turned surface