Microstructure and mechanical properties of selective laser melting of (TiH2+TiB2)/AA7075 composite powders [(TiH2+TiB2)/AA7075复合粉末激光选区熔化成形的显微组织与力学性能]

作者：Ouyang S.; Liu Y.^*; Shen J.; Xiao X.

来源：Materials Science and Engineering of Powder Metallurgy, 2020, 25(3): 197-205.

• 7075 alloy
• Mechanical property
• Microstructure
• Selective laser melting
• TiB2
• TiH2

0.6%-1.4% submicron TiH2 and 0.8% nano-TiB2 particles (mass fraction, the same as below) were added into AA7075 powders, low-energy ball milled (TiH2+TiB2)/AA7075 composite powders were used to fabricate composites by selective laser melting (SLM). Microstructures and mechanical properties of SLMed composites with different TiH2 additive amounts were studied. The results show that the addition of submicron TiH2 and nano-TiB2 particles can significantly inhibit the cracks of SLMed AA7075 composites. The cracks can be completely eliminated when 1.4%TiH2 and 0.8%TiB2 are added. When the TiH2 additive amount increases from 0.6% to 1.4%, columnar grains in the microstructure are all transformed into equiaxed grains, and the average grain size is refined to 1.38 μm from 2.33 μm. When the TiH2 additive amount is 1.4%, the tensile strength, yield strength and elongation of the AA7075 composites are 360 MPa, 328 MPa and 12.0%, respectively. After T6 heat treatment, the properties are further improved. The tensile strength and yield strength increase to 461 MPa and 394 MPa, respectively, and the elongation increases to 15.3%. ? 2020, Editorial Office of Materials Science and Engineering of Powder Metallurgy. All right reserved.

• 单位
  华南理工大学