Research on Microstructure and Mechanical Properties of Brazed Joint of Al0.3CoCrFeNi High Entropy Alloy and YG15 Hard Alloy
The AlxCoCrFeNi high-entropy alloy exhibits excellent toughness and corrosion resistance,making it an ideal material for demanding service conditions such as deep space exploration and geological drilling.However,the shortcomings of low hardness and poor friction and wear performance limit further applications.The outstanding features of cemented carbide are its ultra-high hardness and good wear resistance.To address the limitations of AlxCoCrFeNi alloys and create components that combine high toughness with high hardness,this study employed BNi2 brazing material to join YG15 cemented carbide with Al0.3CoCrFeNi high-entropy alloy.The investigation focused on the influence of brazing temperature on the microstructure and mechanical properties of the YG15/Al0.3CoCrFeNi brazed joint.The results revealed the following microstructural features:The central region of the brazed joint is dominated by Ni(s,s).On the high-entropy alloy side,a diffusion zone formed due to mutual diffusion between BNi2 and the matrix during brazing.Furthermore,the W(s,s)are observed in the YG15 interface side.The typical microstructure of the joint is as follows:YG15/W(s,s)/Ni(s,s)+Cr0.8Ni0.2/HEA+Cr5B3/Al0.3CoCrFeNi.Interestingly,as the brazing temperature increased,the shear strength of the joint initially increased and then decreased.Ultimately,joint failure occurred near the cemented carbide parent material within the brazed seam.Under the process parameters of 1 080 ℃ for 10 minutes,the joint achieved a maximum shear strength of 354 MPa.This study successfully achieved brazing connections between high-entropy alloys and cemented carbides,resulting in the YG15/Al0.3CoCrFeNi composite component.These findings offer new perspectives for preparing composite components of high-entropy alloys and cemented carbides in extreme service environments.
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