Effect of Cold Compaction Pressure on Porous NiAl Articles Produced by Using Space Holder Urea via VCS

Authors : Gülizar Sarıyer, Hasan Erdem Çamurlu

Pages : 106-116

Doi:10.55546/jmm.1460140

View : 18 | Download : 29

Publication Date : 2024-06-26

Article Type : Research

Abstract :Porous NiAl samples were obtained by using 20, 40, 60 vol.% space holder urea particles. The urea particle size was in the range of 150-300 µm. Pressures of 50, 100, 200 and 300 MPa were applied by cold press to the mixtures formed by nickel, aluminum, preformed NiAl powders and urea particles. The dimensions, macrostructure, microstructure and compressive strength of the parts produced with different cold compaction pressures were analyzed after volume combustion synthesis (VCS). The aim of the study is to determine the cold compaction pressure which provides the closest dimensional changes after VCS, in samples having different urea amounts. These samples will be used for forming a multi-stack article in a further study. Since a high difference in dimensional change of different layers during VCS will lead to cracking and separation, similar dimensional change is required for different layers in a multi-stack sample design. The samples which were cold pressed with 300 MPa pressure sometimes contained cracks after they were taken out of the die after cold pressing or after VCS. Therefore, they could not be subjected to characterization. The closest dimensional change and higher compressive strength values after VCS were obtained in samples having different urea contents, when they were cold pressed at 200 MPa. The highest mean compressive strength (218.8±29.5 MPa) was attained in the sample which was prepared with 20% urea particles and which was cold compacted with 200 MPa.
Keywords : NiAl, yanma sentezi, boşluk oluşturucu metodu, gözenekli intermetalik