Correct

线膨胀

/ xiàn péngzhàng / 
Strokes

Example

As a Noun

linear expansion

1
Xiàn
线
péngzhàng
膨胀
xìng
性

linear expansibility/expansivity

2
Xiàn
线
péngzhàng
膨胀
xìshù
系数

linear expansion coefficient