TY - JOUR
T1 - Microstructure and mechanical properties of directed energy deposited U75V/15–5PH structurally graded material
AU - Zhang, Bo
AU - Wang, Huaming
AU - He, Bei
AU - Ma, Chen
AU - Li, An
AU - Liu, Dong
N1 - Publisher Copyright:
© 2021
PY - 2022/3/25
Y1 - 2022/3/25
N2 - In this study, 15–5 precipitation hardening (PH) martensitic steel powder was successfully deposited on U75V eutectoid pearlitic steel to form structurally graded material (SGM) using directed energy deposition (DED) technology. Microstructure evolution mechanism and mechanical properties of U75V/15–5PH SGM were investigated systematically. Results show that the microstructural transition zone (MTZ) is formed above the fusion line due to the dilution effect of eutectoid pearlitic steel. The phase composition of MTZ consists of martensite, retained austenite, and carbides, which is distinct from that of directed energy deposited 15–5PH steel. MTZ possesses the highest microhardness owing to the solid solution strengthening and second phases strengthening of carbon elements provided by eutectoid pearlitic substrate. Special intrinsic thermal cycles of DED lead to the formation of heat affected zone (HAZ) below the fusion line, in which the spheroidization phenomenon of lamellar cementite occurs. The spheroidization degree of lamellar cementite in HAZ is exacerbated with increasing distance from the fusion line. Compared with wrought U75V substrate, the lower tensile strength of SGM is mainly attributed to the weak phase boundaries strengthening of granular pearlite at the bottom of HAZ.
AB - In this study, 15–5 precipitation hardening (PH) martensitic steel powder was successfully deposited on U75V eutectoid pearlitic steel to form structurally graded material (SGM) using directed energy deposition (DED) technology. Microstructure evolution mechanism and mechanical properties of U75V/15–5PH SGM were investigated systematically. Results show that the microstructural transition zone (MTZ) is formed above the fusion line due to the dilution effect of eutectoid pearlitic steel. The phase composition of MTZ consists of martensite, retained austenite, and carbides, which is distinct from that of directed energy deposited 15–5PH steel. MTZ possesses the highest microhardness owing to the solid solution strengthening and second phases strengthening of carbon elements provided by eutectoid pearlitic substrate. Special intrinsic thermal cycles of DED lead to the formation of heat affected zone (HAZ) below the fusion line, in which the spheroidization phenomenon of lamellar cementite occurs. The spheroidization degree of lamellar cementite in HAZ is exacerbated with increasing distance from the fusion line. Compared with wrought U75V substrate, the lower tensile strength of SGM is mainly attributed to the weak phase boundaries strengthening of granular pearlite at the bottom of HAZ.
KW - 15–5PH stainless steel
KW - Directed energy deposition
KW - Mechanical properties
KW - Microstructure
KW - Structurally graded material
UR - https://www.scopus.com/pages/publications/85120862335
U2 - 10.1016/j.jallcom.2021.163001
DO - 10.1016/j.jallcom.2021.163001
M3 - 文章
AN - SCOPUS:85120862335
SN - 0925-8388
VL - 898
JO - Journal of Alloys and Compounds
JF - Journal of Alloys and Compounds
M1 - 163001
ER -