Materials Chemistry and Physics 296 (2023) 127177 Available online 12 December 2022 0254-0584/© 2022 Elsevier B.V. All rights reserved. Evaluation of in-situ synthesised titania-zirconia-boron carbide composite cladding on Ti6Al4V substrate using continuous wave fbre laser Anand M. Murmu a, b , Sambit K. Parida a, * , Alok K. Das b a National Institute of Advanced Manufacturing Technology, Ranchi, 834003, India b Indian Institute of Technology (ISM), Dhanbad, 826004, India HIGHLIGHTS • Composite cladding (TiC, TiB 2 , ZrB 2 , TiO 2 , and ZrO 2 ) is synthesised in-situ on Ti6Al4V alloy substrate by laser cladding. • Infuence of wt.% B 4 C on the microstructure, hardness, wear, and erosion resistance of the cladding was investigated. • The hardness of the claddings is improved (3.4 times higher than the substrate) and the coeffcient of friction is decreased. • Claddings are found to have a good performance against erosion tests at normal and at 750 ◦ C. • No fracture from nanoindentation tests in all the cladding samples is found indicating good resistance to fracture. A R T I C L E INFO Keywords: Laser cladding In-situ synthesis Composite Fibre laser Zirconia Microstructure Microhardness Wear mechanism ABSTRACT In this work, titanium metal matrix composite (TiC, TiB 2 , TiO 2 , ZrB 2 ) cladding was synthesised by irradiating a fbre laser beam on a mixture of Ti6Al4V alloy, ZrO 2 , B 4 C powders pre-placed on Ti6Al4V alloy plate. The effect of varying wt.% of B 4 C on the microstructure, hardness, erosion, and wear properties of the composite cladding were investigated using XRD, XPS, EBSD, FESEM with EDAX, nano-indentation, and wear tests. Under the exposure of fbre laser on a mixture of preplaced powders, the in-situ formation of TiC, TiB 2 , TiO 2 , and ZrB 2 ceramic particles have taken place and get uniformly dispersed in the molten titanium alloy matrix. The volume fraction of these phases increases with the increasing percentage of B 4 C. A black willow-shaped structure (TiB 2 ) is observed in sample BM3 (30 wt% of B 4 C), along with grey cellular dendrites (TiC) dispersed uniformly in the matrix. The average microhardness of the claddings increases with the increase of B 4 C contents. The average weight loss of the cladding samples in dry sliding wear tests decreases with increasing the B 4 C content. The maximum microhardness of 1582.4HV 300 is recorded in BM3 cladding, which is almost four times higher than the substrate material. The decrease in the average value of maximum nano-indentation depth with an increase in the content of B 4 C is in good agreement with the results of microhardness tests. The hardening of the cladding is also accompanied by increased values of parameters H/E (hardness(H)/Young’s modulus (E)) and H 3 / E 2 (0.133), indicating better resistance to crack formation during indentation even at higher loads showing the cladding is hard as well as tough. The grain size variation and volume fraction of TiC–TiB 2 obtained from electron backscatter diffraction test results agrees with cladding having these properties. The coeffcient of friction (0.15–0.25) is found to be lower than the substrate material (~0.3). The claddings also show good erosion resistance at ambient, 250 ◦ C, 350 ◦ C and 750 ◦ C. 1. Introduction Titanium and its alloys have been extensively used in various ap- plications of aerospace, chemical processing, power generation, marine, sports, medical and automobile industries due to its specifc properties such as low density, high specifc strength, high creep resistance, and superior corrosion resistance at low temperature [1,2]. However, the application of these alloys is restricted in various felds of engineering applications, especially in harsh environments, due to their lower wear resistance and low hardness [3,4]. Several methods, such as surface * Corresponding author. Department of Mechanical and Manufacturing Engineering, National Institute of Advanced Manufacturing Technology, Ranchi-3, India. E-mail addresses: anand.murmu@gmail.com (A.M. Murmu), sambitparida@gmail.com, skparida@niamt.ac.in (S.K. Parida), eralok@yahoo.co.in (A.K. Das). Contents lists available at ScienceDirect Materials Chemistry and Physics journal homepage: www.elsevier.com/locate/matchemphys https://doi.org/10.1016/j.matchemphys.2022.127177 Received 12 September 2022; Received in revised form 6 December 2022; Accepted 8 December 2022