| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1987: ¥100,000 (Direct Cost: ¥100,000)
Fiscal Year 1986: ¥200,000 (Direct Cost: ¥200,000)
Fiscal Year 1985: ¥1,600,000 (Direct Cost: ¥1,600,000)
|
|---|
| Research Abstract |
The mechanical properties of composite materials strongly depend on the structure of component phases,such as the dispersion parameters in dispersion hardened alloys. The composite materials for high temperature are usually used under the conditions of holding for long time at high temperature and /or thermal cyclling. Then, the composite materials have to have a stable structure under the conditions besides the strong bonding between the component phases for good stress transfar.
The present project is to lay the foundation for developing excellent refractory materials by producing various kinds of composite materials and studing their interphase boundary, structure-stability and mechanical properties at high temperature.
The results obtained are as follows.
1. Disperesion hardened alloys with thermally stable and non-coherent particles are very excerent for high-temperature strength, because these particles have atractive interaction with dislocation and retard the motion.
2. In the Al-CuAl_2 lamellar-eutectic composite, degradation of the structure of component phases yields due to Ostwald growth during holding at high temperature. This degradation can be improved by producing aligned structure without any reiforcement erminations, because the Ostwald growth occurs preferably at the terminations. In the Mo-TiC lamellar-eutectic composite, interphase-boundary sliding occur and lower the high-temperature strength though the degradation due to the Ostwald growth does not occur.
3. In the Cu-W lamellar composite with a large different in thermal expansion of component phases, many voids form on the interphase boundary during thermal cycling and the strength of composite deteriorades.
4. As mentioned above, the interphase boundary plays an important role in the structure stability and the mechanical properties of composite materials at high temperature.
|
