Microstructure and Properties of(Ti+B4C)/AA7075 Composite Powder by Laser Melting Deposition
The(Ti+B4C)/AA7075 composite powder with 5wt％spherical pure titanium powder and B4C ceramic particles(3wt％,5wt％,10wt％)was prepared by high-energy ball grinding,and several groups of additive samples were prepared by laser melting deposition(LMD)technology.The influence of titanium element and ceramic powder with different B4C contents on the mechanical properties of the composites was studied.The results show that the addition of spherical pure titanium powder and B4C ceramic particles can effectively overcomes the pores and cracking of AA7075 aluminum alloy during LMD molding process.When the mass fraction of B4C is 3wt％,the average microhardness(HV0.2)and tensile strength of the composites are 1388.17 MPa and 336.93 MPa,respectively,which are 41.6％and 68.4％higher than 980.69 MPa and 200.05 MPa of the deposited AA7075 aluminum alloy.Later,with the increase in B4C mass fraction from 3wt％to 10wt％,the tensile strength of the sample gradually decreases,but the wear resistance gradually increases,the average friction coefficient decreases from 0.83 to 0.78,and the wear form changes from adhesive wear to peeling wear.
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