Update

versions: material-ui 0.20.2, react-input-mask 2.0.4

Seems like the API changed a bit:

<InputMask
  mask="(0)999 999 99 99"
  value={this.state.phone}
  disabled={false}
  maskChar=" "
>
  {() => <TextField />}
</InputMask>

Demo

Original

This should do the trick:

<TextField
  ref="phone"
  name="phone"
  type="text"
  value={this.state.phone}
  onChange={this.onChange}
>
  <InputMask mask="(0)999 999 99 99" maskChar=" " />
</TextField>

Demo: