Microwave Sintering of Ti6Al4V: Optimization of Processing Parameters for Maximal Tensile Strength and Minimal Pore Size

Abstract

Pressureless sintering is a powder metallurgical process wherein the powder particles are sintered without the aid of any compressive force. Though this additive manufacturing process is economical, the strength of the component is undermined due to the presence of pores; the elimination of which is a challenge. In this work, the optimal process parameters for the pressureless microwave sintering of a grade 5 titanium alloy that yields higher tensile strength and minimum sizes of pores were obtained. The three process parameters (sintering temperature, heating rate, and holding time) were experimented at five different levels using the design of experiments (DOE). Post sintering, the tensile strength was assessed as per ASTM standard B925-15, while the pore size was evaluated, non-destructively, using micro-computed tomography (μ-CT). The optimal process parameters that yielded minimum size pores were: sintering temperature—1293 °C, heating rate— 6.65 C/minute; and holding time—72 min.

Design and development of 3D printing assisted microwave sintering of elbow implant with biomechanical properties similar tohuman elbow

“…In the research article published by our group earlier, experiments were conducted on cadaveric human elbow bones. The flexural strength of the humerus and ulna bones were 128.43 ± 6.17 MPa and 135.16 ± 30.43 MPa, respectively (Singh et al , 2018c). The flexural strength of the developed Ti6Al4V sintered implant overlaps with the elbow bone.…”

“…Post extraction, the implant was cleaned using a wire brush for any leftover mold debris attached to the surface of the sintered implant. The effect of processing parameters of the sintering process was studied earlier (Singh et al, 2018b). The microwave pressureless sintering process was optimized for obtaining maximum strength, density and minimum shrinkage in an earlier publication by the authors and has been published elsewhere (Singh et al, 2018a).…”

“…This manufacturing process has an inherent capability to produce porous structures at optimized process parameters at low cost and with operational ease. The authors in their earlier publications had performed a multi-parametric optimization of the Polyjet rapid prototyping followed by a microwave sintering process for various desired output responses such as pore size, compressive strength and tensile strength (Singh et al, 2018a(Singh et al, , 2018b.…”

Multi-Objective Optimization of Selective Laser Melting Processes for Minimizing Energy Consumption and Maximizing Product Tensile Strength

“…These studies include identifying the optimized process parameters that lead to the maximal tensile strength [24], deposition orientation optimization [25], and establishing a differential evolution that optimizes the model to achieve good tensile strength [26], to name a few [27,28]. For other AM processes, optimizing processing parameters to maximize the tensile strength for microwave sintering of Ti6Al4V [29] and selective electron beam melting (SEBM) of stainless steel 316L parts were investigated [30]. However, the modeling and optimization of the tensile strength of SLM processed parts are still lacking.…”

Effects of Simulation‐Guided Microwave Presintering Process on the Preparation and Final Properties of Pure Ceramic Rings: Lower Sintering Temperature and Higher Mechanical Properties

“…Currently, conventional sintering is restricted by its natural impediments of uneven temperature and long heating time, whereas microwave sintering features a fast heating speed and more uniform heating and delivers consistent temperature fields [6][7][8]. Microwave sintering technology is broadly adopted in the preparation of other materials: BCTZ piezoelectric ceramics [9], BaTiO 3 ceramics [10], lithium-ion battery electrodes (Li 2 TiO 3 ceramics) [11], ZnO-based piezoresistive materials [12], Si 3 N 4 ceramics [13], Ni-TiC composites [14], Cu-MWCNT nanocomposites [15], graphite alkene-ceramic composites [16], BaTiO 3 -Ag high-energy capacitors [17], various composite materials and hardened alloy materials [18,19], high-performance heat-resistant molybdenum materials [20], and titanium alloy materials [21]. Nevertheless, while utilizing microwave sintering, there are circumstances where the sample fails to absorb microwaves uniformly at low temperatures, leading to the results of uneven heating and potential cracks on the final products.…”