Additive Manufacturing of Ti-48Al-2Cr-2Nb Alloy Using Gas Atomized and Mechanically Alloyed Plasma Spheroidized Powders.

Igor Polozov,Ivan Goncharov,Artem Kantyukov,Jia-Ning Zhu,Anatoly Popovich,Nikolay Razumov,Alexey Silin,Vera Popovich

doi:10.3390/ma13183952

Igor Polozov, Ivan Goncharov + Show 6 more

Open Access

https://doi.org/10.3390/ma13183952

Copy DOI

Abstract

In this paper, laser powder-bed fusion (L-PBF) additive manufacturing (AM) with a high-temperature inductive platform preheating was used to fabricate intermetallic TiAl-alloy samples. The gas atomized (GA) and mechanically alloyed plasma spheroidized (MAPS) powders of the Ti-48Al-2Cr-2Nb (at. %) alloy were used as the feedstock material. The effects of L-PBF process parameters—platform preheating temperature—on the relative density, microstructure, phase composition, and mechanical properties of printed material were evaluated. Crack-free intermetallic samples with a high relative density of 99.9% were fabricated using 900 °C preheating temperature. Scanning electron microscopy and X-Ray diffraction analyses revealed a very fine microstructure consisting of lamellar α2/γ colonies, equiaxed γ grains, and retained β phase. Compressive tests showed superior properties of AM material as compared to the conventional TiAl-alloy. However, increased oxygen content was detected in MAPS powder compared to GA powder (~1.1 wt. % and ~0.1 wt. %, respectively), which resulted in lower compressive strength and strain, but higher microhardness compared to the samples produced from GA powder.

Highlights

Gamma TiAl-based intermetallic alloys are attractive materials for structural high-temperature applications due to their high specific strength at room and elevated temperatures, good creep, and oxidation resistance [1]
In this work it was demonstrated that pre-alloyed spherical gas atomized (GA) and mechanically alloyed plasma spheroidized (MAPS) powders of TiAl-based
In this work it was demonstrated that pre-alloyed spherical GA and MAPS powders of TiAlalloy can be used to fabricate crack-free samples using the laser powder-bed fusion (L-PBF) process with high-temperature based alloy can be used to fabricate crack-free samples using the L-PBF process with highplatform preheating

Summary

Introduction

Gamma TiAl-based intermetallic alloys are attractive materials for structural high-temperature applications due to their high specific strength at room and elevated temperatures, good creep, and oxidation resistance [1]. These properties make them promising candidates for replacing nickel-based superalloys in gas turbine engines [2]. While TiAl alloys possess high strength, their poor ductility and brittleness at room temperatures severely complicate their processability by conventional manufacturing techniques and limit their application [5]. Casting followed by hot isostatic pressing (HIP) has been used to conventionally fabricate TiAl alloy parts [6]; this approach has its limitations in terms of high cost and design flexibility. AM is a promising way to manufacture intermetallic alloy parts since it offers significant advantages in terms of design freedom and cost

Objectives

Methods

Results

Conclusion