Matrix strengthening, solid solution

Taking into account that the volume content, size, distribution and properties of the reinforcing boride phase practically do not change with the alloying studied here, the strengthening of the ternary and quaternary eutectic alloys should be attributed practically in full to solid- solution strengthening of the titanium alloy matrix. 

Despite the fact that the reinforcing Ti5Si3 fibers are not continuously aligned within the a-titanium matrix the rule of mixture can be applied because the aspect ratio 11 /dF = 50 is fairly high and sufficient enough to transfer the load from the solid solution strengthened matrix to the fibers [25]. Assuming that the solid solution a-Ti(Si) matrix has a flow stress of about om = Em = 300 MPa at room temperature, the effective flow stress of the... 

Table 2 presents mechanical properties of alloys with a matrix on the base of solid solution of niobium and molybdenum, dispersion-strengthened with chemical compounds, and also alloy with an additional frame strengthening owing to eutectoid TiFe. 

The nickel base alloys are produced from a group of alloys which have chemical compositions generally over 50 % nickel and less than 10 % iron. They are mainly strengthened by intermetallic precipitation in an austenitic matrix. The cobalt base alloys have a high Co content (40 to 70 %X high Cr (over 20 %), high W (7 to 15 %) and they are strengthened by a combination of carbides and solid solution hardeners. 

It has been reported that the addition of zinc into Ni-P matrix has a remarkable influence on its microstructure, mechanical and electrochemical properties [25],In the present study, novel Ni-B-Zn ternary alloy coatings have been synthesized through conventional electrodeposition process. A comparison of properties of Ni-B and Ni-B-Zn coatings in their as deposited state has been presented to elucidate the role of zinc addition on structural, thermal, mechanical properties. A significant improvement in the mechanical properties has been noticed due to solid solution strengthening of Ni-B matrix. 

Microstmcture of Rodent after casting is composed of large grains/den-drites of the austenite matrix, which is the solid solution of nickel strengthened chromium and molybdenum. The matrix is additionally strengthened by dispersion of molybdenum silicide precipitates. A small number of carbide and aluminum oxide particles were also observed. The presence of eutectics y-P rather weakens the structure of the alloy. 

All Ni and Fe—Ni-based superalloys are alloyed with Al. This leads to a two-phase matrix consisting of the y-(Ni, Fe, Al) solid solution phase (fee, Al stmeture) and the intermetallic y -NisAl phase (LI2 stmeture), which has a superlattice structure relative to the fee stmeture of the y phase. The binary Al—Ni phase diagram in Fig. 3.1-128 shows clearly that the y phase is stable up to the melting range. The matrix phase y is solid solution strengthened by allo3dng additions of Cr, Mo, W, and... 

Nickel-based alloys, which form the bulk of alloys produced, are basically nickel-chrome alloys with a face-centered cubic solid-solution matrix containing carbides and the coherent intermetallic precipitate y-NijlAfTi). This latter precipitate provides most of the alloy strengthening and results in useful operating temperatures up to 90% of the start of melting. Further additions of aluminum, titanium, niobium, and tantalum are made to combine with nickel in the y phase, and additions of molybdenum, tungsten, and chromium strengthen the solid solution matrix. 

Heat treatment. Solid-solution-strengthened high-temperature alloys are normally supplied in the solution-heat-treated condition unless otherwise specified. In this condition, microstructures generally consist of primary carbides dispersed in a single-phase matrix, with essentially clean grain boundaries. This is usually the optimum condition for the best elevated temperature properties in service and the... 

An example of the type of data associated with solution hardening it is the mission of our models to explain was shown in fig. 8.2(a). For our present purposes, there are questions to be posed of both a qualitative and quantitative character. On the qualitative side, we would like to know how the presence of foreign atoms dissolved in the matrix can have the effect of strengthening a material. In particular, how can we reconcile what we know about point defects in solids with the elastic model of dislocation-obstacle interaction presented in section 11.6.2. From a more quantitative perspective, we are particularly interested in the question of to what extent the experimental data permit a scaling description of the hardening effect (i.e. r oc c") and in addition, to what extent statistical superposition of the presumed elastic interactions between dislocations and impurities provides for such scaling laws. 

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