Product Code: ICAL06_M103

Microstructure and Mechanical Properties of Laser Net Shape Manufactured Inconel 718 and Ti-6Al-4V Components
Authors:
Minlin Zhong, Tsinghua University; Beijing Peoples Republic of China
Jinjiang He, Tsinghua University; Beijing Peoples Republic of China
Wenjin Liu, Tsinghua University; Beijing Peoples Republic of China
Presented at ICALEO 2006

Refractory intermetallic compound Nb3Al is expected as a candidate for structural materials operated at much higher temperatures compared to conventional Ni superalloys. However, Nb3Al is difficult to fabricate by conventional methods. This paper presents the research on combination of the synthesizing of A15 Nb-Ti-Al and bcc/B2-type through pure powder blend of Nb, Ti, Al and the fabrication of a laminated-structure Nb-Ti-Al composite by multi-layer deposition, with focusing on their mechanical properties. The A15 phase intermetallic alloys with high strength at high temperature show brittle tendency during multi-layer laser deposition, which can only be used as some kind of coatings within limited height. On the other hand, the bcc/B2-type Nb-Ti-Al alloys show good ductility with free defects in laser fabrication. In this paper, the ductile bcc/B2 Nb-40Ti-15Al and brittle Nb-12Ti-22Al alloy were in situ deposited layer by layer alternately. The varied laminated composites were then fabricated with the control of thickness of each layer. The microstructures in both ductile and brittle layers and at the interface were analyzed by SEM. The compression test were carried out on a Gleebe 1500. Compression tests were performed both perpendicular and paralleled to the deposition direction at room temperature and 900. The fracture toughnesses were also tested for the laminated composites. The results show that these kind of laminated composites have a combination of high temperature strength and room-temperature toughness. The thickness ratio of Nb-40Ti-15Al/ Nb-12Ti-22Al=1:1 has good mechanical properties for high temperature applications.