Creep and fatigue properties of high temperature silicides and their composites

Mechanical behaviour of Ti5Si3 based alloys and composites

“…It is interesting to note that the grain size plays such an important role, even in the dislocation creep regime. Such a behaviour, where the regime of dislocation creep is strongly influenced by the grain size has been observed in the case of MoSi 2 as well 28 . Since the number of slip systems is limited, and climb requires the atoms of a component to cross more than one atomic spacing for maintaining the crystal structure, the diffusion of atoms along the grain boundaries becomes necessary for accommodation of the local strain gradients.…”

“…However, the stress exponent of Ti 5 Si 3 with 5 μm average grain size is higher than that of MoSi 2 with almost similar grain size. The creep activation energy of the fine-grained Ti 5 Si 3 is higher than that of MoSi 2 at temperatures around 1200 o C, 28 which could be attributed to the more complex structure of the former.…”

Microstructure and sliding-wear behavior of tungsten-reinforced W-Ni-Si metal-silicide in-situ composites

“…During mechanical milling and grinding, no microcracking and brittle spalling phenomena were encountered. There are also no microcracks observable at the corners of the Vickers indentation marks, even when the test load is as high as 1000 g, while such indentation-cracking phenomena were widely reported for many binary metal-silicide alloy such as Mo 5 Si 3 , Ti 5 Si 3 , MoSi 2 , Cr 3 Si, etc., [12,23,26] and the indentation-cracking phenomenon was proposed and widely accepted as a method to evaluate the fracture toughness of brittle materials such as Cr 3 Si by correlating the relationship between the indentation load and the cracking length. [27] All of the aforementioned experimental phenomena imply that the in-situ incorporation of the rapidly solidified strong and tough tungsten primary phase in the W-Ni-Si intermetallic matrix noticeably enhanced the strength and toughness, which is naturally beneficial for their performance when employed as both structural and wear-resistant materials.…”

“…[2,[19][20][21] Moreover, it is widely demonstrated that in-situ incorporation of ductile refractory metallic phases can significantly enhance the toughness and strength of many refractory-metal silicide-based alloys. [22][23][24][25][26][27] However, to the knowledge of the authors, no information is currently available in the open literature on the development of multicomponent, multiphase metal-silicide-matrix composites as potential wear-resistant materials. In this article, W-Ni-Si silicide intermetallic-matrix composites with in-situ reinforcement of refractory tungsten particles are fabricated using a newly invented water-cooled copper-mold laser melting furnace by the LASMELT* process.…”

MoSi2 oxidation resistance coatings for Mo5Si3/MoSi2 composites

“…Therefore, many researches have been done to improve the mechanical properties of MoSi 2 in material design and preparing technique since the early 1970s. In material design, adding the second phase, such as ZrO 2 , SiC, Si 3 N 4 , TiB 2 , and Al 2 O 3 , to enhance the properties of the matrix, was usually viewed as a major method [1][2][5][6][7].…”