This paper sums up the cutting, heat treatment of 4. J32 low-expansion alloy applied in a space instrument, analyses the reasons why 4j32 is difficult to be cut.

This paper introduces the casting precipitation properties, their effects on the alloy microstructure and the methods to eliminate the precipitation of the Low-expansion superalloy GH909. and GH907.

Hypereutectic Al-Si alloy which has small proportion, low coefficient of thermal expansion, good wear resistance and dimensional stability is an ideal piston material.