Laser directed energy deposition of FeSi/SS 316L advanced bimetallic high-speed rotors: From material characterization to performance evaluation

Microtexture in additively manufactured Ti-6Al-4V fabricated using directed energy deposition

Technical basis of using laser direct energy deposition as a high-throughput combinatorial method for DC-cast Al-Mn alloy development

Additive manufacturing of corrosion-resistant maraging steel M789 by directed energy deposition

Impact of hot isostatic pressing on the mechanical and microstructural properties of additively manufactured Ti–6Al–4V fabricated using directed energy deposition

Effect of laser rescanning on microstructure and mechanical properties of direct energy deposited AISI 316L stainless steel

The creep properties of a laser-directed energy deposition (L-DED) technique manufactured Inconel 718 (IN718) was investigated at 650 °C/700 MPa. Microstructure and creep properties of L-DED IN718 samples were tailored by various post heat treatments involving homogenization heat treatment with temperature ranging from 1080 to 1180 °C + double aging and hot isostatic pressing (HIP). Microstructural changes and their influence on the creep behavior and fracture mechanism were observed and discussed. The results show that L-DED sample heat treated by a simple double aging exhibits a 49% increase in creep lifetime tr and a comparable creep elongation ɛf when compared to the wrought material, due to the reserved coarse dislocation cell substructure from the L-DED process. The loss of dislocation cell structure and the coarsening of grains at higher temperature of heat treatments contributes to a shorter tr, εf, but faster ε̇min (minimum creep rate). The present work demonstrates that a simultaneous improvement of creep strength and creep elongation can be achieved in the case of a coarse-grained L-DED IN718 by a double aging treatment which can preserve both the strengthening precipitates and an appropriate size of dislocation cells.

In situ X-ray imaging of pore formation mechanisms and dynamics in laser powder-blown directed energy deposition additive manufacturing

Pore defects and corrosion behavior of AISI 316L stainless steel fabricated by laser directed energy deposition under closed-loop control

Additive manufacturing of nickel based super alloys such as IN718 is highly desirable since they have a wide range of applications in high performance structures. Compared to conventional methods, laser processing allows for near net shaping of complex geometries. However, laser processing can result in very complex microstructures including meta-stable phases, grain boundary segregation of precipitates, dendritic grains and cellular microstructure. Describing elastic properties of such structures can be quite challenging due to these features. This article explores the use of resonant ultrasound spectroscopy (RUS) to characterize the elastic properties of IN718 samples fabricated using Laser Directed Energy Deposition (DED). For initial estimates of the elastic constants, ultrasonic wave (longitudinal and shear) velocities measured at 5MHz and 2.25 MHz respectively. The initial assumption was that the eventual structure will be orthotropic and the 9 elastic constants were determined using a combination of RUS and propagating wave experiments. A finite element approach was adopted to model this system and to minimize the values of elastic constants. The results seem to suggest that the secondary phases such as Laves will influence the eventual anisotropy of the bulk structure.

Controlling microstructure of FeCrMoBC amorphous metal matrix composites via laser directed energy deposition

Non-dimensional process maps for residual stress in laser directed energy deposition

Mechanical and microstructural properties of laser direct energy deposited 15–5 PH and SS 316L stainless steel

The feasibility of using laser direct energy deposition (DED) additive manufacturing (AM) to synthesize a commercial, aluminum-manganese alloy of the 3000 series was evaluated by comparing the microstructures of AM and direct-chill (DC) cast alloys. The purpose of this work was to establish a baseline for accelerating Al alloy discovery using combinatorial materials synthesis. Feedstock alloy powder was prepared by mixing pure metal element or binary alloy powders via ball-milling and fabricating bulk samples using laser DED AM. Compositional accuracy of both powder feedstock and laser DED AM samples was controlled within 10% of the target. The effect of homogenization on the evolution of second-phase particles as a function of temperature and time was found to be similar in both laser DED AM and DC-cast materials.

Experimental investigation of laser remelting in directed energy deposition (DED) of CPM-9V

A process optimization framework for laser direct energy deposition: Densification, microstructure, and mechanical properties of an Fe[sbnd]Cr alloy