Wear-resistant boride composites with high percentage of reinforcement phase
A highly wear resistant sintered, hot pressed, or otherwise compacted ceramic composite material is described, consisting of two discrete phases of the form AlxMgyB14 where x and y ≦1 or like hard, orthorhombic compounds, and TiB2 or like Group IVB transition metal di-borides, and with an unexpectedly high contentof transition metal di-boride in the range from 40 to 90 percent (28 to 85 volume percent).
Low load multiple scratch tests of ceramics and hard metals
Abstract Abrasion is caused by the repeated scratching of materials by individual particles in an abrasive, often under fairly light loads. This process has been simulated by carrying out scratch tests on a range of ceramics and hard metals. An array of different scratches was carried out on each sample with a different number of repeats along the same track for each scratch. The magnitude of the damage was measured by the width of the scratches. The frictional force between the indenter and test sample was also measured. Although the width of single pass scratches in some of the harder materials was smaller than in softer materials, in multiple pass scratches, the final widths of scratches in some of the harder materials were greater than in the softer materials. This was due to differences in the contribution of fracture in the development of damage in multiple pass scratches. It was found that fracture was a predominant form of damage to both hard metals and ceramics. In the case of the hard metals the fracture was on a fine scale, but with the ceramics fracture occurred on a larger scale, often removing large fragments of material. These results, and the results of the friction measurements are correlated with the results of a microstructural examination of the mechanisms that occurred. They are also compared with a microstructural assessment of the early stages of wear in the abrasion of these materials.
The measuriment of ferromagnets magnetic characteristics using Labview software
The digital method of measurement and registration of dynamic loops hysteresis family of magneto-soft materials where, along with known analogues from electro-technical steel, magnetic materials with considerably smaller specific magnetic losses such as amorphous alloys on the basis of iron, is offered. Tests of magnetic properties of materials are carried out on the base of the hardware-software measuring complex in which along with the standard established electric equipment and USB oscillograph for realization of a digital method, the software for the personal computer developed in the environment of visual programming of Borland Delphi 7.0, connected through the ActieveX technology with the Labview 7.0 environment, is applied. The software allows carrying out input of basic data concerning geometry of prototypes of cores from magnetic materials and numbers of rounds of the magnetizing and measuring windings located on their surface. Experimental data on voltage at measuring winding terminals are processed by means of the virtual integrator in a Labview package. The developed software provides the possibility of saving the obtained hysteresis loop in the form of a text file, and creation of the hysteresis loops family on the virtual oscillograph screen.