Author: Robert David NixonPublisher:
ISBN:
Category :
Languages : en
Pages : 374
Book Description
Kinetics and Mechanisms of Creep in Sintered Alpha Silicon Carbide and Silicon Carbide Whisker Reinforced Silicon Nitride and Mullite
Author: Robert David NixonKinetics and Mechanisms of Primary and Steady-state Creep in Sintered Alpha Silicon Carbide
Author: Jay Edgar LaneKinetics and Mechanisms of Creep in Sintered Alpha Silicon Carbide and Niobium Carbide
Author: Robert F. DavisPublisher:
ISBN:
Category :
Languages : en
Pages : 60
Book Description
Constant stress compressive creep studies and complementary TEM research have been conducted on sintered alpha-SiC and on dense polycrystalline NbCO737 to determine the kinetics and the mechanisms of deformation as a function of temperature and stress. In the former material, the values of the stress exponents of 1.44-1.71 indicate that either viscous flow or grain boundary sliding is controlling creep. However, the values of the activation energies (approx. 400kJ/mol below 1920K and approx. 850 kJ/mol above 1920K) coupled with the TEM studies which show the presence of considerable dislocation glide activity and the formation of corrugated grain boundaries and the formation of porosity on the boundaries and voids at the triple points. Originator supplied keywords include: Hot Isostatic pressing; Climb; Stacking faults; Diffusion.
Engineered Materials Abstracts
Author: Crack Growth During High Temperature Creep Conditions in Silicon Carbide Whisker-reinforced Mullite and Silicon Carbide Whisker-reinforced Silicon Nitride
Author: Michael H. GodinPublisher:
ISBN:
Category : Cracking process
Languages : en
Pages : 312
Book Description
International Aerospace Abstracts
Author: Ceramic Abstracts
Author: Kinetics and Mechanisms of High-Temperature Creep in Silicon Carbide. II. Chemically Vapor Deposited
Author: C. H Carter (Jr)Publisher:
ISBN:
Category :
Languages : en
Pages : 10
Book Description
Chemically vapor deposited (CVD) silicon carbide was subjected to constant compressive stresses (110 to 220 MN/sq m) at high temperatures (1848 to 2023 K) in order to determine the controlling steady-state creep mechanisms under these conditions. An extensive TEM study was also conducted to facilitate this determination. The strong preferred crystallographic orientation of this material causes the creep rate to be very dependent on specimen orientation. The stress exponent, n, in the equation epsilon alpha sigma was calculated to be 2.3 below 1923 K and 3.7 at 1923 K. The activation energy for steady-state creep was determined 175 to be + or - 5 kJ/mol throughout the temperature range employed. At temperatures between 1673 and 1873 K, the controlling creep mechanism for CVD SiC is dislocation glide, which is believed to be controlled by the Peierls stress, Although the activation energy does not change, the increase in the stress exponent for samples deformed at 1923 K suggests that the controlling creep mechanism becomes dislocation glide/climb controlled by climb. Additional keywords: reprints; microstructure; x ray scattering.
The Kinetics and Mechanisms of High Temperature Creep of a SiC Whisker-reinforced Si3N4
Author: David Alan KoesterKinetics and Mechanisms of High-temperature Creep in Chemically Vapor Deposited and Reaction-bonded Silicon Carbide
Author: Calvin Haywood CarterPublisher:
ISBN:
Category : Creep testing machines
Languages : en
Pages : 410
Book Description