Force and Microstructure Variation of SLM Prepared AlMgSc Samples during Three-Point Bending.

Daming Nie,Pu Zhang,Ruilong Du,Fangyan Shen,Yili Fu,Jason Gu

doi:10.3390/ma15020437

Abstract

Lightweight parts manufactured by metal selective laser melting (SLM) are widely applied in machinery industries because of their high specific strength, good energy absorption effect, and complex shape that are difficult to form by mechanical machining. These samples often serve in three-dimensional stress states. However, previous publications mainly focused on the unidirectional tensile/compressive properties of the samples. In this paper, AlMgSc samples with different geometric parameters were prepared by the SLM process, and the variation of force and microstructure during three-point bending were systematically investigated. The results demonstrate that the deformation resistance of these samples has good continuity without mutation in bending, even for brittle materials; the bending force-displacement curves exhibit representative variation stages during the entire bending process; the equivalent bending strength deduced from free bending formula is not applicable when compactability is less than 67%. The variations of grain orientation and size of the three representative bending layers also show regularity.

Highlights

selective laser melting (SLM) manufactured parts occupy widespread application because of light density [1,2,3]and complex modeling, which present challenges in mechanical machining [4]
The SLM parts are manufactured into bracket connectors on the Airbus A350 XWB [5] and could be designed as cooling channels with optimized mechanical and heat dissipation performance [6], which are employed in the combustion chambers or turbines of aircraft engine
The samples with diverse geometric parameters were manufactured by SLM process, and the mechanical behavior and microstructure variation regulations of samples in three-point bending were investigated

Summary

Introduction

SLM manufactured parts occupy widespread application because of light density [1,2,3]. An Al3Sc lattice formed in aluminum matrix has a L12 structure that belonged to fcc structure, while the side length of the crystal cell is diverse This attribution arouses strong and stable lattice distortion for hindering dislocation movement [14], significantly improving the mechanical properties and reducing the average diameter of grain size of the samples processed by SLM [15]. Nine groups of specimen with different geometric parameters are acquired (Figure 2) and numbered in sequence of compatibility from small to large It can be observed from (b) and (c) that the grids of the samples are clear and the dimensional accuracy is high, manifesting outstanding forming performance of AlMgSc material

Experimental Methods

Microstructure Analysis

Findings

Conclusions