نوع مقاله : مقاله پژوهشی
نویسندگان
1 Azadi Square, Mashhad, Razavi Khorasan Province, Iran
2 فردوسی مشهد
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Heavy tungsten alloys are made by liquid phase sintering for application in protective weights, radiation shields, and anti-missiles. The change in each of the production parameters of these alloys affects the mechanical behavior of these alloys. The aim of this research is to assess the effect of annealing heat treatment cyclic on the bonding strength of tungsten particles with the matrix. Tungsten alloy with a chemical composition of 93.5W-5.4Ni-1.95Fe (in wt.%) is first compressed in a plastic mold (cold isostatic) following by liquid phase sintering at 1480 °C and two cycles of annealing heat treatment. In order to study the mechanical properties, tensile and hardness tests are used. Also, the microstructures and fracture surfaces (after tensile test) of the samples are examined using optical and scanning electron microscopes. The obtained results show that due to the thermal stresses during cooling and heating through the cyclic annealing heat treatment, the matrix phase is penetrated into the interface of tungsten particles which causes a decrease in the contiguity (from 0.44 to 0.31). Also, the cyclic annealing heat treatment reduces the impurities in the interface between tungsten particles and the matrix, resulting in an increase in strength (from 842 MPa to 960 MPa). Comparison of fracture surfaces of samples with annealing cyclic shows the change of brittle fracture mechanism to soft fracture. Keywords: Heavy tungsten alloys; Sintering; Heat treatment; Particles/matrix interface; Contiguity.
کلیدواژهها [English]
)
ارسال نظر در مورد این مقاله