ISSN:
1573-4803
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract In the present paper, the crystallography of isothermal transformation and decomposition ofβ, phase have been studied by means of transmission electron microscopy and diffraction in the CuZnAl shape memory alloy. It has been proved that the bainite formed inβ 1, matrix when the samples were transformed isothermally at moderate temperature. The crystallography of the isothermal bainitic transformation is identical to that of martensite in the same system. When the specimens were aged at moderate temperatures for longer time, the bainite and matrix decomposed to equilibrium phases. The decomposition process can be summarized as follows: $$\begin{gathered} bainite (9R) \to 9R + \alpha \left( {fcc} \right) \to \alpha + \beta \left( {bcc} \right) \hfill \\ matrix (B2) \to 2H + B2 \to \beta \left( {bcc} \right) \hfill \\ \end{gathered} $$ There are definite orientation relationships among these phases during the decomposition process and they are shown below: $$\begin{gathered} \left( {111} \right)_\alpha \parallel \left( {001} \right)_B ,\left[ {0\bar 11} \right]_\alpha \parallel \left[ {\bar 110} \right]_B \hfill \\ \left( {111} \right)_\alpha 5^ \circ away from \left( {110} \right)_\beta ,\left[ {0\bar 11} \right]_\alpha \parallel \left[ {1\bar 1\bar 1} \right]_\beta \hfill \\ \left( {110} \right)_M \parallel \left( {001} \right)_{2H} ,\left[ {001} \right]_M \parallel \left[ {010} \right]_{2H} \hfill \\ \end{gathered} $$ Thus, the crystallography of isothermal transformation and decomposition ofβ 1 phase and the sequence of transitions have been revealed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01045762
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