Lets first of all understand Young's modulus of a substance. It is also called modulus of elasticity and is a measure of the stiffness of a solid material.
In other words it is a number that measures resistance of an object to being deformed elastically when a stress is applied to the object. Elastic modulus
# λ -= "stress"/ "strain"#
where stress is the force causing the deformation, and strain is the ratio of the change in value of a particular parameter to its original value.
Since strain is a dimensionless quantity, λ has units of stress.
Now, we know that amount of thermal expansion of any solid is related to its coefficient of linear expansion
#sigma_x=alpha lambda (T−T_"ref")#
#T#is uniform temperature of the solid metal sample and #T_"ref"#is reference temperature, say room temperature.