Unlike conventional materials removal methods, additive manufacturing (AM) is based on a novel materials incremental manufacturing philosophy. Additive manufacturing implies layer by layer shaping and consolidation of powder feedstock to arbitrary configurations, normally using a computer controlled laser. The current development focus of AM is to produce complex shaped functional metallic components, including metals, alloys and metal matrix composites (MMCs), to meet demanding requirements from aerospace, defence, automotive and biomedical industries. Laser sintering (LS), laser melting (LM) and laser metal deposition (LMD) are presently regarded as the three most versatile AM processes. Laser based AM processes generally have a complex non-equilibrium physical and chemical metallurgical nature, which is material and process dependent. The influence of material characteristics and processing conditions on metallurgical mechanisms and resultant microstructural and mechanical properties of AM proc...

Laser additive manufacturing of metallic components: materials, processes and mechanisms

https://docs.lib.purdue.edu/cgi/viewcontent.cgi?article=1037&context=mepubs

Additive manufacturing of Ti6Al4V alloy: A review

A review on selective laser sintering/melting (SLS/SLM) of aluminium alloy powders: Processing, microstructure, and properties

This article reviews published data on the mechanical properties of additively manufactured metallic materials. The additive manufacturing techniques utilized to generate samples covered in this review include powder bed fusion (e.g., EBM, SLM, DMLS) and directed energy deposition (e.g., LENS, EBF3). Although only a limited number of metallic alloy systems are currently available for additive manufacturing (e.g., Ti-6Al-4V, TiAl, stainless steel, Inconel 625/718, and Al-Si-10Mg), the bulk of the published mechanical properties information has been generated on Ti-6Al-4V. However, summary tables for published mechanical properties and/or key figures are included for each of the alloys listed above, grouped by the additive technique used to generate the data. Published values for mechanical properties obtained from hardness, tension/compression, fracture toughness, fatigue crack growth, and high cycle fatigue are included for as-built, heat-treated, and/or HIP conditions, when available. The effects of test...

Metal Additive Manufacturing: A Review of Mechanical Properties

Titanium and nickel alloys represent a significant metal portion of the aircraft structural and engine components. When these critical structural components in aerospace industry are manufactured with the objective to reach high reliability levels, surface integrity is one of the most relevant parameters used for evaluating the quality of finish machined surfaces. The residual stresses and surface alteration (white etch layer and depth of work hardening) induced by machining of titanium alloys and nickel-based alloys are very critical due to safety and sustainability concerns. This review paper provides an overview of machining induced surface integrity in titanium and nickel alloys. There are many different types of surface integrity problems reported in literature, and among these, residual stresses, white layer and work hardening layers, as well as microstructural alterations can be studied in order to improve surface qualities of end products. Many parameters affect the surface quality of workpieces, and cutting speed, feed rate, depth of cut, tool geometry and preparation, tool wear, and workpiece properties are among the most important ones worth to investigate. Experimental and empirical studies as well as analytical and Finite Element modeling based approaches are offered in order to better understand machining induced surface integrity. In the current state-of-the-art however, a comprehensive and systematic modeling approach based on the process physics and applicable to the industrial processes is still missing. It is concluded that further modeling studies are needed to create predictive physics-based models that is in good agreement with reliable experiments, while explaining the effects of many parameters, for machining of titanium alloys and nickel-based alloys.

Machining induced surface integrity in titanium and nickel alloys: A review

The present invention describes an assembly for manufacture of a component by hot isostatic pressing comprises a first workpiece (4') and a second workpiece (6') and a method of manufacturing a component using such an assembly. The first workpiece (6') and second workpiece (4') are assembled to define a cavity (28). Removable tooling pieces (30,31) are provided to the assembly which further define the cavity (28) and which are shaped to apply a forging load to a powder (26) within the cavity (28) during hot isostatic pressing.

Assembly and method of manufacture of a component by hot isostatic pressing using tooling pieces for creating a cavity with the parts of the component

In a hot isostatic pressing (HIP) process, for example for securing blades (5) to a disc (3) to form a blisk (1), the temperature of the powder (6) to be consolidated is raised to a predetermined temperature, which may be the eventual required pressing temperature, before the pressure rise to the pressing pressure is initiated. If the powder is a titanium alloy and the process employs steel tooling pieces (4), the application of pressure occurs only when the temperature has risen to the extent that the steel is harder than the titanium alloy.

Manufacture of an article by hot isostatic pressing

Nickel-Legierung für Turbinenmotorbauteil Nickel alloy for turbine engine component

A surface treatment device for applying a surface treatment medium to an article is provided with the surface treatment device having an application member for applying the surface treatment medium to the article and and an electrode which applys an electrical potential between the application member and the article. The device provides localised treatment to the article and can remove oxide layers or the like from metallic materials without removing or damaging the underlying metallic material.

Method of treating a component of a gas turbine engine

A method of manufacturing an article (10, fig.3) comprising the steps of arranging a plurality of workpieces 12 into an abutting relationship and holding them in that position with a tooling member 14, enclosing the workpieces and tooling member in a vacuum bag 16, evacuating the vacuum bag, heating and applying pressure to the vacuum bag to diffusion bond the workpieces to form the article, and removing the vacuum bag and tooling member from the article. Preferably the method uses hot isostatic pressing to bond the workpieces. The surfaces of the tooling member may be coated with a stop off material such as boron nitride to prevent diffusion bonding between the member and the article. A powder may be arranged between the workpieces to aid diffusion bonding. Preferably, the article is a component of a gas turbine engine, the component being formed from Titanium or Titanium aluminide alloy.

Wayne Eric Voice

Papers

Assembly and method of manufacture of a component by hot isostatic pressing using tooling pieces for creating a cavity with the parts of the component

Manufacture of an article by hot isostatic pressing

Nickel-Legierung für Turbinenmotorbauteil Nickel alloy for turbine engine component

Method of treating a component of a gas turbine engine

Method of diffusion bonding