Effect of Post Processes on Mechanical Properties of 3D Printed Ti6Al4V Gears


KAYA M. Ş. , Ece R. E. , KELEŞ Ö., Qader A., Yilbas B. S.

JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE, vol.31, no.8, pp.6300-6309, 2022 (Peer-Reviewed Journal) identifier identifier

  • Publication Type: Article / Article
  • Volume: 31 Issue: 8
  • Publication Date: 2022
  • Doi Number: 10.1007/s11665-022-06706-7
  • Journal Name: JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE
  • Journal Indexes: Science Citation Index Expanded, Scopus, PASCAL, Aerospace Database, Applied Science & Technology Source, Aquatic Science & Fisheries Abstracts (ASFA), Chemical Abstracts Core, Communication Abstracts, Compendex, Computer & Applied Sciences, INSPEC, Metadex, Civil Engineering Abstracts
  • Page Numbers: pp.6300-6309
  • Keywords: 3D printing, gears, mechanical properties, structures, Ti6Al4V alloy, TITANIUM-ALLOY, BEHAVIOR, TEMPERATURE, SURFACE

Abstract

Ti6Al4V alloys are widely used in the space industry because of their high toughness to weight ratio. Additive manufacturing of printed parts minimizes the difficulties faced by conventional processing such as precision machining and forming. In the present study, mechanical and metallurgical properties of the gear manufactured by Electron Beam Machine with a method of Powder Bed Fusion are investigated. The influence of post isostatic pressing, heat treatment, and nitriding processes on surface characteristics and material properties are examined. In the mechanical tests, tensile, fatigue, and impact EB printed samples are studied, while microhardness, nitride case depth are assessed using analytical tools including SEM, EDS, and microhardness tester. It is found that the hot isostatic pressing and heat treatment improve the mechanical properties of the samples such that yield stress increases from 930 to 1010 MPa and ultimate tensile stresses from 990 to 1046 MPa. Although gas nitriding improves the surface hardness of the samples from 320 to 543 HV, significantly lowers the fatigue life from 3124 cycles to 790 cycles of the samples under 42.5 kN fatigue load. After hot isostatic pressing, the beta-phase columnar structures are delineated and form the boundary arrays, which cluster the alpha-phase structures. The heat treatment causes the corrugation of beta-phase structures.