diff --git a/src/MaterialManager.py b/src/MaterialManager.py
index bdfbaa2..ce4a4e0 100644
--- a/src/MaterialManager.py
+++ b/src/MaterialManager.py
@@ -7,22 +7,38 @@ def __init__(self, params: list):
         self.params = params
         # other configurations
 
-    def changeMaterial(self, material) -> bool:
+  def changeMaterial(self, material) -> bool:
         returnText = ""
+        textBaseForValidMaterial = "Material is changed to"
 
         match material:
             case materialType.Titanium:
                 self.carManager.setMaterial(materialType.Titanium)
-                returnText = "Material is changed to Titanium."
+                returnText = f"{textBaseForValidMaterial} Titanium."
 
             case materialType.Carbon:
                 self.carManager.setMaterial(materialType.Carbon)
-                returnText = "Material is changed to Carbon."
+                returnText = f"{textBaseForValidMaterial} Carbon."
+
+            case materialType.AlloyX:
+                self.carManager.setMaterial(materialType.AlloyX)
+                returnText = f"{textBaseForValidMaterial} AlloyX."
 
             case _:
-                returnText = "Material seletion is invalid."
+                returnText = "Material selection is invalid."
 
         return self._announceMaterial(returnText)
 
+
+
+
     def _announceMaterial(self, text: str) -> bool:
-        return self.announcer(text)
+   returnValue = False
+   try:
+       returnValue = self.announcer(text)
+   except:
+       print("Announcement of material type is failed.")
+       returnValue = False
+   finally:
+       return returnValue
+
diff --git a/src/Util.py b/src/Util.py
index 81ab0ba..5abfeff 100644
--- a/src/Util.py
+++ b/src/Util.py
@@ -1,3 +1,3 @@
 from enum import Enum
 
-materialType = Enum('Titanium', 'Carbon')
+materialType = Enum('Titanium', 'Carbon', 'AlloyX')