Thermal expansion and spontaneous strain associated with the normal-incommensurate phase transition in melilites
Thermal expansion and spontaneous strain associated with the normal-incommensurate phase transition in melilites
复制标题
与黄长石中正常不通约相变相关的热膨胀和自发应变
DOI：
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发表时间：
1992
期刊：
影响因子：
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通讯作者：
J. Liebertz
中科院分区：
文献类型：
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作者：
Sharon L. Webb;C. R. Ross;J. Liebertz
本文测量了两种材料在正常-非公度相变过程中的线性热膨胀。高温(正常相)数据的最小二乘拟合得到瞬时线性热膨胀系数的在T中线性的表达式，
$$Alpha_1=裂缝{1}{L}裂缝{{dl}}{{dt}}$$
对于akermanite：
$$egin{已收集}Alpha_{[100]}=6.901(2)IMES 10^{-6}+1.834(2)IMES 10^{-8}T HFILL\Alpha_{[100]}=-2.856(1)IMES 10^{-6}+11.280(1)IMEs 10^{-8}T HFILL\结束{已收集}$$
对于硬质石岩：
$$egin{已收集}Alpha_{[100]}=15.562(5)IMES 10^{-6}-1.478(3)IMES 10^{-8}T HFILL\Alpha_{[100]}=-11.115(5)IMES 10^{-6}+11.326(3)IME 10^{-8}T HFILL\结束{已收集}$$
尽管相变温度在10°C以内有相当大的应变，暗示着高阶相变，但似乎存在有限的ΔV相变，相变被归类为“弱一级”。
AbstractThe linear thermal expansions of åkermanite (Ca2MgSi2O7) and hardystonite (Ca2ZnSi2O7) have been measured across the normal-incommensurate phase transition for both materials. Least-squares fitting of the high temperature (normal phase) data yields expressions linear in T for the coefficients of instantaneous linear thermal expansion,
$$alpha _1 = frac{1}{l}frac{{dl}}{{dT}}$$
for åkermanite:
$$egin{gathered} alpha _{[100]} = 6.901(2) imes 10^{ - 6} + 1.834(2) imes 10^{ - 8} T hfill \ alpha _{[100]} = - 2.856(1) imes 10^{ - 6} + 11.280(1) imes 10^{ - 8} T hfill \ end{gathered} $$
for hardystonite:
$$egin{gathered} alpha _{[100]} = 15.562(5) imes 10^{ - 6} - 1.478(3) imes 10^{ - 8} T hfill \ alpha _{[100]} = - 11.115(5) imes 10^{ - 6} + 11.326(3) imes 10^{ - 8} T hfill \ end{gathered} $$
Although there is considerable strain for temperatures within 10° C of the phase transition, suggestive of a high-order phase transition, there appears to be a finite ΔV of transition, and the phase transition is classed as “weakly first order”.