Fatigue property investigating and finite element stress analysis of Ti alloys clasps by selective laser melting in different build orientations

doi:10.3877/cma.j.issn.1674-1366.2018.05.002

Abstract

Abstract:

Objective

The purpose of this study was to investigate the mechanical properties of selective laser melting (SLM) Ti-6Al-4V clasps of different build orientations.

Methods

A total of 48 clasps were made from three different build orientations SLM and cast Ti-6Al-4V alloys (as CAST, SLM0, SLM45, SLM90 groups) . The stress values and distribution induced in clasps were calculated by finite element analysis. All specimens were subjected to the insertion/removal tests, which were carried out in artificial saliva on a metal abutment tooth for 7200 cycles to simulate 5-year clinical use. After all tests, one clasp of each group was subjected to three-point bending test to get the fracture surface of clasp arms, which were observed by SEM to examined the microstructure and fracture mechanism. All data were statistically analyzed by SPSS 20.0. The statistical significance was set at α = 0.05.

Results

The finite element analysis showed that the maximum von Mises were located on the middle part of the retainer arms and that the values of the 0.50 mm undercut clasps were far lower than the elastic limit of titanium alloy. In addition, for the 0.25 mm undercut, the decrease in retention force of the SLM90 group was less than that of CAST group (P<0.05) , while for the 0.50 mm undercut, the decrease in the retention force of SLM90 was less than that of CAST, SLM0 and SLM45 groups (P<0.05) . Fracture surface analysis indicated that the cracks were intergranular.

Conclusions

SLM specimens had finer grains compared with cast specimens. The fracture mode in SLM, especially SLM90 clasps, was ductile, while that in the cast clasps was brittle. In addition, SLM Ti-6Al-4V clasps could be engaged into 0.50 mm undercut, and SLM90 clasps had better fatigue resistance than SLM45, SLM0 and cast clasps.

Key words: Finite element analysis, Selective laser melting, Ti-6Al-4V, Orientation, Anisotropic

Wenqiang Xie, Jieqi Wang, Meihua Zheng, Xiaoyu Li, Wen Zhang, Peiling Wei. Fatigue property investigating and finite element stress analysis of Ti alloys clasps by selective laser melting in different build orientations[J]. Chinese Journal of Stomatological Research(Electronic Edition), 2018, 12(05): 271-277.

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Figures/Tables 11

References 24

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化学成分	铸造卡环	SLM卡环( ± s)
钛(Ti)	88.0 ~ 91.0	89.00 ± 2.00
铝(Al)	5.5 ~ 6.5	6.40 ± 0.40
钒(V)	3.5 ~ 4.5	4.00 ± 0.15

化学成分	铸造卡环	SLM卡环( ± s)
钛(Ti)	88.0 ~ 91.0	89.00 ± 2.00
铝(Al)	5.5 ~ 6.5	6.40 ± 0.40
钒(V)	3.5 ~ 4.5	4.00 ± 0.15

材料	ρ(kg·m^-3)	E(GPa)	UTS(MPa)	0.2%YS(MPa)	泊松比
钛合金卡环	4400	116	1100	900	0.30
金属基牙	4500	220	-	-	0.33

材料	ρ(kg·m^-3)	E(GPa)	UTS(MPa)	0.2%YS(MPa)	泊松比
钛合金卡环	4400	116	1100	900	0.30
金属基牙	4500	220	-	-	0.33

组别		r值	P值
0.25 mm倒凹		?	?
?	铸造组	-0.983	0.000
?	SLM0组	-0.995	0.000
?	SLM45组	-0.948	0.000
?	SLM90组	-0.914	0.000
0.50 mm倒凹		?	?
?	铸造组	-0.980	0.000
?	SLM0组	-0.977	0.000
?	SLM45组	-0.947	0.000
?	SLM90组	-0.979	0.000

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