The research involves the addition of 5 vol.%TiB_(2)particles into AA8009 alloy powder to synthesize TiB_(2)/AA8009 composite parts produced via laser powder bed fusion(LPBF).The addition of the TiB_(2)particles cause...The research involves the addition of 5 vol.%TiB_(2)particles into AA8009 alloy powder to synthesize TiB_(2)/AA8009 composite parts produced via laser powder bed fusion(LPBF).The addition of the TiB_(2)particles causes the TiB_(2)/AA8009 composites with and without annealing have lower compressive strength than AA8009 alloy due to the change of the strengthening mechanism.The results further indicated that solid solution strengthening was the main strengthening mechanism of the LPBF AA8009 alloy at room temperature whereas Orowan strengthening became the primary strengthening factor after annealing at 673 K.In contrast,Orowan strengthening always remained the main strengthening mechanism for the TiB_(2)/AA8009 composite,irrespective of the annealing temperature.In addition,after annealing of the LPBF parts at 673 K,the compressive yield strength(CYS)of the unblended AA8009 alloy specimens had a~2.5 times greater reduction(from 705±16 to 459±30 MPa)compared to that of the composite TiB_(2)/AA8009 samples(from 466±23 to 368±3 MPa).Therefore,TiB_(2)particles can suppress the drop in yield strength of LPBF AA8009 alloy below 673 K,providing a theoretical and experimental basis for the applications of both LPBF AA8009 and TiB_(2)/AA8009 alloys at low and medium temperatures.展开更多
Laser powder bed fusion(L-PBF)-built triply periodic minimal surface(TPMS)structures are designed by implicit functions and are endowed with superior characteristics,such as adjustable mechanical properties and light-...Laser powder bed fusion(L-PBF)-built triply periodic minimal surface(TPMS)structures are designed by implicit functions and are endowed with superior characteristics,such as adjustable mechanical properties and light-weight features for bone repairing;thus,they are considered as potential candidates for bone scaffolds.Unfortunately,previous studies have mainly focused on different TPMS structures.The fundamental understanding of the differences between strut and sheet-based structures remains exclusive,where both were designed by one formula.This consequently hinders their practical applications.Herein,we compared the morphology,mechanical properties,and biocompatibility of sheet and strut-based structures.In particular,the different properties and in vivo bone repair effects of the two structures are uncovered.First,the morphology characteristics demonstrate that the manufacturing errors of sheet-based structures with diverse porosities are comparable,and semi-melting powders as well as the ball phenomenon are observed;in comparison,strut-based samples exhibit cracks and thickness shrinking.Second,the mechanical properties indicate that the sheet-based structures have a greater elastic modulus,energy absorption,and better repeatability compared to strut-based structures.Furthermore,layer-by-layer fracturing and diagonal shear failure modes are observed in strut-based and sheet-based structures,respectively.The in vivo experiment demonstrates enhanced bone tissues in the strut-based scaffold.This study significantly enriches our understanding of TPMS structures and provides significant insights in the design of bone scaffolds under various bone damaging conditions.展开更多
基金P.Wang acknowledges the support from the National Natural Science Foundation of China(No.52105385)the Stable Support Plan Program of Shenzhen Natural Science Fund(No.20220810132537001)the Guangdong Basic and Applied Basic Research Foundation(Nos.2020A1515110869 and 2022A1515010781).
文摘The research involves the addition of 5 vol.%TiB_(2)particles into AA8009 alloy powder to synthesize TiB_(2)/AA8009 composite parts produced via laser powder bed fusion(LPBF).The addition of the TiB_(2)particles causes the TiB_(2)/AA8009 composites with and without annealing have lower compressive strength than AA8009 alloy due to the change of the strengthening mechanism.The results further indicated that solid solution strengthening was the main strengthening mechanism of the LPBF AA8009 alloy at room temperature whereas Orowan strengthening became the primary strengthening factor after annealing at 673 K.In contrast,Orowan strengthening always remained the main strengthening mechanism for the TiB_(2)/AA8009 composite,irrespective of the annealing temperature.In addition,after annealing of the LPBF parts at 673 K,the compressive yield strength(CYS)of the unblended AA8009 alloy specimens had a~2.5 times greater reduction(from 705±16 to 459±30 MPa)compared to that of the composite TiB_(2)/AA8009 samples(from 466±23 to 368±3 MPa).Therefore,TiB_(2)particles can suppress the drop in yield strength of LPBF AA8009 alloy below 673 K,providing a theoretical and experimental basis for the applications of both LPBF AA8009 and TiB_(2)/AA8009 alloys at low and medium temperatures.
基金National Natural Science Foundation of China(Grant Nos.51975073,82172429,51805052)China Scholarship Council(CSC).
文摘Laser powder bed fusion(L-PBF)-built triply periodic minimal surface(TPMS)structures are designed by implicit functions and are endowed with superior characteristics,such as adjustable mechanical properties and light-weight features for bone repairing;thus,they are considered as potential candidates for bone scaffolds.Unfortunately,previous studies have mainly focused on different TPMS structures.The fundamental understanding of the differences between strut and sheet-based structures remains exclusive,where both were designed by one formula.This consequently hinders their practical applications.Herein,we compared the morphology,mechanical properties,and biocompatibility of sheet and strut-based structures.In particular,the different properties and in vivo bone repair effects of the two structures are uncovered.First,the morphology characteristics demonstrate that the manufacturing errors of sheet-based structures with diverse porosities are comparable,and semi-melting powders as well as the ball phenomenon are observed;in comparison,strut-based samples exhibit cracks and thickness shrinking.Second,the mechanical properties indicate that the sheet-based structures have a greater elastic modulus,energy absorption,and better repeatability compared to strut-based structures.Furthermore,layer-by-layer fracturing and diagonal shear failure modes are observed in strut-based and sheet-based structures,respectively.The in vivo experiment demonstrates enhanced bone tissues in the strut-based scaffold.This study significantly enriches our understanding of TPMS structures and provides significant insights in the design of bone scaffolds under various bone damaging conditions.