Effect of Build Parameters on the Compressive Behavior of Additive Manufactured CoCrMo Lattice Parts Based on Experimental Design

Abstract

Due to their high specific strength, toughness, and corrosion and wear resistance characteristics, CoCrMo alloys are widely used in different industries and applications: wind turbines and jet-engine components, orthopedic implants, dental crowns, etc. The aim of this paper is to investigate the effect of lattice parameters on the compressive behavior of laser powder bed fusion (LPBF) parts from CoCrMo material. Build orientation, volume fraction, and lattice type are chosen as input parameters or control factors, and compressive yield strength (σy), elastic modulus (E), and specific energy absorption are chosen as the output or performance parameters for optimization. The Taguchi experimental design method is used in the arrangement of lattice parameters during experimental studies. The level of importance of the lattice parameters on σy, E, and specific energy absorption is determined by using analysis of variance (ANOVA). At the same material volume fractions, Diamond specimens showed higher σy and specific energy absorption than Gyroid and Primitive specimens, except σy at 0.4 volume fraction, where a Gyroid specimen showed the best result. The experimental and statistical results revealed that volume fraction and build orientation were found to be the major and minor effective factors, respectively, for all performance parameters (σy, E, and specific energy absorption). The effect of volume fraction on σy, E, and specific energy absorption was found to be 85.11%, 91.83%, and 57.71%, respectively. Lattice type was found to be the second-ranking factor, affecting σy, E, and specific energy absorption with contributions of 11.04%, 6.98%, and 39.40%, respectively. Multi objective optimization based on grey relation analysis showed that a Diamond specimen with 0.4 volume fraction and 45° build orientation was the best parameter set for the investigated performance outputs.

An experimental and numerical study about the effect of substrate thickness on dimensional deviation in laser powder bed fusion process

“…During production of the specimens, gas atomized spherical CoCrMo powder material with 10-45 μm particle size [27] and Concept Laser M2 LPBF machine with 50 μm layer thickness, 180 W laser power, 1500 mm s −1 scanning speed, 60 μm hatch spacing and meander scanning strategy were used.…”

The effect of geometrical parameters on dimensional deviation in LPBF produced TPMS lattices: a numerical simulation based study

“…Table 2 shows the ANOVA results. In this table, Adj SS (adjusted sum of squares) are measures of variations, Adj MS (adjusted mean squares) means how much variation the related parameter explains, F-value is used to calculate p-value and P-value defines significance level which shows the accuracy of the design of experiment [3]. Here, a lower P-value means higher significance.…”

“…Different TPMS structures show different mechanical behaviours under axial loading conditions. For instance, primitive structures show stretch-dominated, and gyroid and diamond structures show bending-dominated behaviour under axial loadings [3].…”

Prediction of Compressive Behavior of Laser-Powder-Bed Fusion-Processed TPMS Lattices by Regression Analysis

“…However, for specific energy absorption, gyroid lattices outperformed when compared with diamond and primitive lattices [13]. Gülcan et al stated that for different volume fractions, generally, diamond lattices showed higher yield stress and specific energy absorption than gyroid and primitive lattices produced by LPBF from CoCr material [14]. Zhang et al's study revealed that LPBF-produced 316L TPMS lattice structures can be manufactured by conventional manufacturing methods; however, due to its need for molds, fixtures, or machining, the manufacturing of these structures with these methods is expensive.…”