D. Guichard

Bio: D. Guichard is an academic researcher from Snecma. The author has contributed to research in topics: Inconel 625 & Powder metallurgy. The author has an hindex of 1, co-authored 2 publications receiving 66 citations.

Le procédé de mise en forme ISOPREC

Abstract: ISOPREC® est un procede de metallurgie des poudres dans lequel un moule particulierement elabore est rempli de poudre puis densifie en Compression Isostatique a Chaud (C.I.C.). Apres compaction, le moule est elimine mecaniquement ou chimiquement, et une piece aux cotes finales est obtenue. Les deformations importantes et complexes qui interviennent au cours de la densification ne peuvent etre predites manuellement et un outil de modelisation numerique est developpe, de facon a minimiser les cycles et les couts de developpement des pieces. Des exemples d'application de cette technologie dans les domaines aeronautiques et spatiaux sont presentes. Les proprietes mecaniques elevees obtenues sur les pieces associees a la grande precision dimensionnelle du procede font d'ISOPREC® une reponse au difficile challenge de la recherche de l'amelioration des performances au moindre cout.

Hot isostatic pressing of a near α-Ti alloy: Temperature optimization, microstructural evolution and mechanical performance evaluation

Abstract: Hot isostatic pressing (HIP) shows distinct advantages in the manufacture of difficult-to-process materials into components with geometric complexity and high mechanical performance. In this work, a near-α titanium alloy Ti–6Al–2Zr–1Mo–1V (TA15) designed for service temperatures of ~500 °C in the aerospace industry was processed by HIP at three representative temperatures. A systematic study on the phase constitutions, microstructural evolution, and tensile properties measured at 20, 500, 600, and 700 °C was carried out for the assessment of HIP TA15 specimens. The relationships among HIP temperature, crystallographic characteristic, and mechanical performance of HIP TA15 were elucidated in detail. Spark plasma sintering (SPS) was selected to compare with the HIP technique regarding the fabrication of TA15 alloy. The tensile strength and ductility of the HIP specimens at 500 °C were 14.8% and 52.8% higher than those of the SPS counterparts. Furthermore, the high-temperature tensile properties of HIP TA15 specimens were comparable to those of the forged IMI 685 and even better than those of sintered Ti60 parts. These findings can serve as a guideline for the HIP process of TA15 alloy and the HIP parameter optimization for other near-α Ti alloys applied in harsh environments.

Effect of Hot-Isostatic-Pressing Parameters on the Microstructure and Properties of Powder Ti-6Al-4V Hot-Isostatically-Pressed Samples

Abstract: Ti-6Al-4V powders have been hot-isostatically-pressed (“HIPped”) using a range of hot-isostatic-pressing (“HIPping”) conditions, and the effects on microstructure and mechanical properties have been assessed. The properties were measured on test samples machined from HIPped powder billets and on samples that contained the as-HIPped surface. The fatigue limit of samples that contained the as-HIPped surface was improved by using a new HIPping procedure. The machined samples that had been HIPped at 1203 K (930 °C) exhibited a better balance of properties than those HIPped at 1153 K (880 °C) or 1293 K (1020 °C). The fine microstructure, formed from the martensitic structure of the atomized powder, coarsens with the increase of temperature or time during HIPping. These changes have been correlated with the corresponding changes in properties and with the fracture surfaces. The significance of these observations, especially the fatigue properties of samples that contain the as-HIPped surface, is discussed in terms of the properties of net-shape HIPped components.